Optimisation of polymer concrete for the

manufacture of the precision tool

machines bases

By

Header Haddad

BSc & Master (Honours) in Advanced Manufacturing Technologies

A thesis submitted in fulfilment of the requirements for the

degree of Doctor of Philosophy

Faculty of Engineering & Industrial Sciences

Swinburne University of Technology

Hawthorn, Melbourne, Australia

August 2013

II

Declaration

I certify that except where due acknowledgement has been made, the work is that

of the author alone; the work has not been submitted previously, in whole or in

part, to qualify for any other academic award; the content of the thesis is the result

of work which has been carried out since the official commencement date of the

approved research program.

Header Haddad

III

Acknowledgments

I acknowledge the limited guidance of my principal supervisor Dr. Igor Sbarski in

the experimental work and other related aspects of my research. I also would like

to thank Dr. Mohammad Al Kobaisi, and Professor Robert Sanks, from RMIT

University, for their continuous support and valuable guidance throughout my

research. I acknowledge financial support in the form of a scholarship provided by

Advanced Manufacturing Cooperative Research Centre and ANCA Pty Ltd.

(AMCRC/ANCA).

My thanks are extended to the following people for their help at various stages of

my PhD research: Professor Emad Gad and Dr. Ibrahim Alsiaidi from the Civil

Engineering at Swinburne University for their advice in conducting the vibration

test for polymer concrete composite system; Dr. Larry Gordon and Sam Quint,

from AMCRC, for their support; and Grant Rivett, from Melbourne University, for

his assistance in conducting the compression and flexural tests for polymer

concrete composite system.

I also acknowledge the continuous support of Professor Pam Green the director of

the research office in Swinburne University, in various stages of my PhD study. I

wish to express my gratitude to my family for their endless support, love and

encouragement throughout my entire education.

Thank you

IV

Publications

Published conference paper

The effect of material composition on thermal expansion and mechanical strength

of polymer concrete used for manufacturing a base of CNC grinding machine.

Header Haddad, Igor Sbarski, Davide McPherson, Ajay Arora, In: Preceeding of

ANTEC 2011, pp. 967-972 .

Published journal paper

Optimization of the polymer concrete used for manufacturing bases for precision

tool machines. Header Haddad Mohamad Alkobaisi. Journal of Composite

material Part B: Engineering, 43, 8, pp. 3061-3068.

Influence of moisture content on thermal and mechanical properties and the

curing behaviour for polymeric matrix and polymer concrete composite. Header

Haddad, Mohamad Alkobaisi. Submited to Materials & Design 49, pp. 850-856.

V

Abstract

One of the main operational drawbacks of the polymer concrete (PC) bases of

precision tool machines is the high coefficient of thermal expansion (CTE). The

non-uniform distribution of thermal expansion for the base under operational

conditions induces high variation in the deflections on the base rails. The rails

have direct contact with other mechanical components that hold the workspace in

precision tool machines, impacting negatively on their accuracy. Reducing the

CTE of the PC base to reach the CTE of the metal inserts (rails, pads, stands etc.) is

essential to enhance the accuracy of the precision machine. Other parameters

affecting performance directly such as damping ratio, flexural strength, moisture,

dimethyl aniline (DMA) (promoter) and maturity need to be optimized to improve

the PC used in the base of precision tool machines. In the present study,

optimization of the PC base was undertaken according to the application

requirements. The optimization process started with the optimization of the resin

monomeric composition to lay the ground for further optimization of the PC

aggregate composition. The optimization of both the PC resin binder and the

composition of the aggregate were based on lowering the CTE and increasing both

the flexural strength and damping ratio, since these properties are essential key

controls for the thermal and mechanical stability of the bases used for precision

tool machinery. Commercial unsaturated polyester (ARAPOL) resin was

investigated along with other copolymers, methyl methacrylate (MMA) and

styrene (St), in various proportions. The proportions of the resin monomer

composition determine the thermal, mechanical and rheological properties of the

resin. It was found that the optimum resin for use as a binder for PC base is 40%

ARAPOL mixed with 60% MMA. In an effort to determine the optimum aggregate

composition, six aggregates (basalt, river gravel, spodumene, fly ash, sand, and

chalk) were investigated. PC samples were prepared with various aggregate

VI

compositions containing the same resin volume fraction (aggregate 83% and resin

17%). Four-point flexural testing was utilized to measure the flexural strength of

PC samples, and the CTE was measured using a custom-built device. The initial

optimum composition with the highest flexural strength and lowest thermal

expansion coefficient was found to be basalt, spodumene and fly ash. A basalt,

sand and fly ash composition was nominated for further optimisation to reduce

the resin volume fraction because of the ability of aggregate composition to adopt

less resin. A reduction in the resin volume fraction (17% - 13%) in the PC reduces

the value of CTE by 31% and flexural strength by 36%. This has no major effect on

the PC base’s structural rigidity because of the large size of the base and the

relatively small loads of the machine mounted on it. However, the damping ratio

reduction is approximately 40%. This shortcoming can be overcome by increasing

the structural damping properties of the whole machine. This can be achieved by

installing a mechanical damper to the PC base to maintain the required damping

ratio. The optimized aggregate composition was validated for the base of precision

tool machinery using ANSYS 13.0 CAE software and comparing various

aggregates compositions. Results show that the optimum composition offers more

thermal stability and variation in the deformation of the base rails is reduced to

negligible levels, which enhances the performance of the precision tool machine.

The optimum composition (filler 87%, resin 13%) also offers the advantage of cost-

effectiveness. The effects of the moulding temperature, mixing technology and the

amount of DMA (promoter) on moulding were investigated, and the technology

for mixing the resin with the aggregate was also investigated. Three mixing

technologies were proposed and the optimum mixing technology nominated

according to the level of mechanical strength of the PC sample. The effect of DAM

amount (promoter) and the moulding temperature were investigated. An

empirical relationship regulating the amount of DMA according to the moulding

temperature was obtained. PC sample compaction was also investigated, and

VII

various PC samples were subjected to a variety of frequencies for packing using a

vibrating table. The optimum frequency is identified based on the mechanical

strength of PC samples. The initial water (moisture) in the coarse aggregate of the

PC composite components was studied, and a volumetric ratio of 1-5% water was

included in the initial resin components. The effect of this water on the curing

process, the CTE and the mechanical properties of both the resin and PC

composites were investigated. It was found that moisture increases the curing time

and the CTE for the resin binder, the PC composite, and the damping factor for the

binding resin. It also decreases the flexural and compressive strength at various

rates. A maturity study of the polymer concrete was conducted, under which the

PC samples were cured at various temperatures for different periods of time.

Flexural strength was measured for each time and temperature used for the

curing. An empirical mathematical model describing the relationship between the

relative flexural strength of PC and the curing time and temperature was obtained.

In essence, this thesis has brought together the most essential aspects required to

optimize polymer concrete for the manufacture of bases for precision tool

machinery. These aspects relate to the PC composite material, polymeric binder,

the effect of moisture on polymer and PC, mixing technology, maturity of PC, and

moulding technology. All of these aspects were connected to the performance of

the precision machine through the investigation of the material properties and the

optimization process in accordance with the optimization criteria of the PC base

used for the precision tool machinery. Results of this research showed

improvements in these aspects and recommendations in terms of resin

compositions, PC composition, DMA, manufacturing process were all adopted by

the industrial partner.

VIII

Significant contributions of the thesis include:

§ The optimization of the chemical composition of the binding resin to be

used as a resin binder in polymer concrete. The purpose of the optimised

resin is to use the most suitable binder when manufacturing bases for

precision tool machinery according to the application requirements. The

optimized resin binder produces the second lowest coefficient of thermal

expansion (CTE), the highest damping factor, the highest flexural strength,

the highest tensile strength, and the shortest curing time and is second in

the ranking for level of hardness compared to other compositions.

§ The nomination of the optimum aggregate composition for polymer

concrete in order to provide the lowest CTE and an acceptable level of

flexural strength within the application requirements.

§ The development of an empirical relationship regulating the amount of

DMA (promoter) according to the moulding temperature of the resin

binder used in manufacturing the bases of precision tool machinery.

§ The identification of the optimum frequency of the vibrating table for the

PC sample to produce the maximum compaction based on the level of

mechanical strength of the PC samples developed.

IX

§ The provision of a fundamental understanding of all PC optimized

parameters (damping factor, CTE, curing, flexural strength) and the main

opposing parameter (moisture).

§ The optimisation of moulding technology in correlation with dimethyl

aniline (DMA) (promoter) amounts and moulding temperature. Also

optimisation of mixing technology within the consideration of aggregate

morphology and on-going resin viscosity increase during the curing.

§ The implementation of a maturing method that enhances the productivity

and the quality of polymer concrete for the base of precision tool

machinery.

§ The development of interdependencies or relationships between

mechanical properties such as flexural strength and the maturing time and

maturing temperature, which can help to predict the flexural strength of

polymer concrete within the curing time and temperature.

§ The conduct of an in-depth study of the effect of moisture on the CTE and

mechanical properties, and on the curing behaviour of both resin and PC

composite system.

X

Abbreviations

ATR-FTIR Fourier transform infrared spectroscopy

BET Brunauer, Emmett, and Teller specific surface area and porosity

BJH Barret, Joyner and Halenda theory to determine the desorption

BPO Benzoil peroxide

CAD Computer aided design

CAE Computer aided engineering

CNC Computer numerical control

CT Computerised morphology

CTE Coefficient of thermal expansion

DMA Dimethyl aniline

DMA Dynamic mechanical analyser

DSC Differential scanning calorimetry

HCl Hydrochloric acid

LDA Logarithmic decrement analyses

MEKP Methyl ethyl ketone peroxide

MMA Methyl methacrylate

MRI Magnetic resonance imaging

MT Mixing technology

NRL Natural rubber latex

NND N, N-diethyl aniline

PC Polymer concrete

SBR Styrene-butadiene rubber

SEM Scanning electron microscopy

TBS Tertiary butyl catechol

TGA Temperature gravimetric analysis

IAB Interfacial adhesion bonding

TMPTMA Terimethylol propane terimethacrylate

VV/VS The ratio of void volume to sample volume in resin

XI

UPE Unsaturated polyester

Symbols

Bf Isothermal bulk modulus of the filler

Bm Isothermal bulk modulus of the matrix

D1 Biggest diameter of particle generations

D2 Smallest diameter of particle generations

D3 Intermediate diameter of particle generations

Ea Activation energy

Gm Shear modulus of the matrix

K The ratio of the biggest particle diameter and smallest particle diameter

K Rate constant for a single scanning in Brouchat model

Mc Maturity of concrete

Mpc Maturity of polymer concrete

n Reaction Order

R The gas constant 8.314 (J/mol °K)

Si Specific surface area of aggregates

Vf Volume fraction of the filler

Vm Volume fraction of the matrix

VP Packing factor

Z Pre-exponential factor

αf Coefficient of thermal expansion of dispersed filler

αm Coefficient of thermal expansion of matrix

β Coefficient of volumetric thermal expansion

ΔH Heat Reaction

δr Thickness of the resin layer

0V The absolute volume

fV Total volume fraction occupied by the solid particles

XII

List of figures

Figure 1.1 CT-3D scanner machine. .......................................................................................... 2

Figure 1.2 CNC grinding tool machine. .................................................................................... 4

Figure 1.3 (A) The tool, (B) grinding wheel arrangement, the (C) spindle and the (C)fixture for more stability and more precision. ...................................................................................... 5

Figure 1.4 Tools of different geometries that can be made with precision tool machine...... 6

Figure 1.5 Manufacturing the core of a mould, a micro mould for a plastic micro gear, and the steel micro gear..................................................................................................................... 7

Figure 2.1 A Generalized chemical structure of unsaturated polyester molecule. .............. 24

Figure 2.2 Styrene chemical structure. .................................................................................... 24

Figure 2.3 Chemical structure of MMA (monomer). ............................................................. 26

Figure 2.4 Chemical structure of MEKP(initiator). ................................................................ 26

Figure 2.5 Chemical structure of DMA ................................................................................... 27

Figure 2.6 Chemical structure of cobalt octoate (promoter) .................................................. 27

Figure 2.2.7 (a) Flank wear versus cutting time, (b) surface roughness versus cutting time obtained using polymer concrete and cast iron beds under wet and dry turning conditions (PCBN inserts). ......................................................................................................................... 57

Figure 2.2.8 Comparison between cast iron and polymer concrete base in terms of (a) acceleration time history and (b) spectrum measured during free vibrations. ................... 58

Figure 2.2.9 Cross-section of the CNC machine bed (Ding, 2010). ....................................... 59

Figure 3.1 Chemical structure of UPE. .................................................................................... 65

Figure 3.2 Schematic configuration is of Malvern Mastersizer X. ........................................ 77

Figure 3.3 The results of particle size distribution of fly ash obtained from the Malvern Mastersizer software that can be converted into Excel.......................................................... 78

Figure 3.4 Zwick universal testing machine. .......................................................................... 81

Figure 3.5 Measuring device coefficient of thermal expansion (CTE). ................................. 83

Figure 3.6 Arrangement inside the heating chamber with other components of the experimental set-up. ................................................................................................................. 84

Figure 3.7 Thermal Advantage software. ............................................................................... 86

Figure 3.8 TA Universal 200 viewing DAM analysis file. ..................................................... 87

Figure 3.9 Flowchart of the procedure for measuring resin viscosity. ................................. 89

Figure 3.10 Experimental arrangements for measuring temperature during the curing of the resin. .................................................................................................................................... 90

XIII

Figure 3.11 DSC Analysis: (a) Precisa 125A Balance; TA Instruments Tzero press; and TA Instruments hermetic aluminium pans. (b) Modulated DSC 2920. (c) Modulated DSC 2920 Furnace. (d) Upper view of modulated DSC 2920 Furnace. ................................................. 93

Figure 3.12 DSC procedures. ................................................................................................... 94

Figure 3.13 ZEISS Supra 40 VP SEM. ...................................................................................... 95

Figure 3.14 Aggregates used in polymer concrete for different compositions. ................... 97

Figure 3.15 Drying aggregates using vacuum chamber. ....................................................... 97

Figure 3.16 Mould mounted on the vibrating table using G-clamps for sample preparation, (a) compression test mould and (b) flexural tests mould. ............................... 99

Figure 3.17 Sample for a compressive test (AS 1012.9-1986). .............................................. 100

Figure 3.18 Gel coated cylindrical steel mould. ................................................................... 101

Figure 3.19 Compression test for polymer concrete sample. .............................................. 101

Figure 3.20 Test settings for flexural strength according to AS 1012.11-2000. ................... 102

Figure 3.21 Fully disassembled rectangular mould for preparing a flexural strength sample. .................................................................................................................................... 103

Figure 3.22 Fully disassembled rectangle mould manufactured and ready to be used. ... 104

Figure 3.23 Sintech 60/D universal testing machine for conducting a flexural test according to AS 1012.11-2000. ............................................................................................... 104

Figure 3.24 Cross-section and exploded assembly drawing for the mould used for preparing a PC sample for the purpose of measuring damping ratio. .............................. 106

Figure 3.25 The accelerometer mounted on PC sample. ..................................................... 107

3.26 The amplifier connected to both the accelerometer and data acquisition system to supply data to the computer.................................................................................................. 108

Figure 3.27 Logarithmic Decrement Analyses (LDA). ......................................................... 109

Figure 3.28 Time domain obtained using Lab View software. ........................................... 110

Figure 3.29 Schematic diagram of CTE custom-built device. .............................................. 111

Figure 4.1 Initiation step for polymerization ........................................................................ 114

Figure 4.2 Propagation step for unsaturated polyester resin .............................................. 115

Figure 4.3 Termination step of unsaturated polyester copolymerization .......................... 116

Figure 4.4 Viscosity versus time for all ARAPOL/styrene compositions .......................... 118

Figure 4.5 Gel time versus ARAPOL volume fraction for ARAPOL/MMA composition. ................................................................................................................................................. 118

Figure 4.6 Gel time versus ARAPOL volume fraction for ARAPOL/ styrene composition. ................................................................................................................................................. 119

XIV

Figure 4.7 Viscosity versus time for all ARAPOL/MMA compositions ............................ 120

Figure 4.8 Exothermic temperature profile during the curing of ARAPOL/styrene compositions. .......................................................................................................................... 122

Figure 4.9 Exothermic temperature profile during the curing of ARAPOL/MMA compositions. .......................................................................................................................... 123

Figure 4.10 25% ARAPOL/styrene sample. ........................................................................ 125

Figure 4.11 Damping factors of all resin compositions versus frequency plotted using universal V4 software from TA instruments. ....................................................................... 125

Figure 4.12 Damping factor of all resins at frequency of 100HZ, ARAPOL/styrene and ................................................................................................................................................. 126

Figure 4.13 Effect of ARAPOL volume fraction on flexural strength. ................................ 128

Figure 4.14 Effect of ARAPOL volume fraction on (a) tensile strength, (b) strain for compositions containing MMA and styrene individually. ................................................. 129

Figure 4.15 Effect of ARAPOL (%) on modulus of elasticity for ARAPOL/Styrene and ARAPOL/MMA. .................................................................................................................... 130

Figure 4.16 Resin samples with various proportions of MMA, ARAPOL and styrene prepared for measuring CTE. ................................................................................................ 131

Figure 4.17 Thermal expansion behaviour of different resins with different proportions of ARAPOL/MMA. .................................................................................................................... 132

Figure 4.18 Thermal expansion behaviour of different resins with different proportions of ARAPOL/styrene. .................................................................................................................. 132

Figure 4.19 CTE for all resin composition versus ARAPOL volume fraction (%).] ........... 133

Figure 4.20 ARAPOL volume fractions versus hardness shore D in ARAPOL/MMA composition............................................................................................................................. 134

Figure 4.21 ARAPOL volume fractions versus hardness shore D in ARAPOL/Styrene composition............................................................................................................................. 135

Figure 5.1 Particle size distributions for all aggregates. ...................................................... 140

Figure 5.2 Recommended number of generations as a function of packing and ratio K. . 143

Figure 5.3 Theoretical packing of particles versus the ratio of smallest to largest generations. ............................................................................................................................. 144

Figure 5.4 SEM of failed PC sample: the failure mechanism is going through the interfacial bonding between filler particles, in this case fly ash. ........................................ 151

Figure 5.5 Samples of polymer concrete of different compositions. ................................... 152

Figure 5.6 SEM images of (a) Spodumene: with hard and sharp textures containing layers, (b) Sand: round and smooth, (c) Fly sh: spherical shape and smooth surface, (d) Chalk: irregular shape with texture. ................................................................................................. 154

XV

Figure 5.7 Viscosity of mixture resin fly ash, resin chalk versus time. ............................... 155

Figure 5.8 CTE of PC composite versus resin volume fraction. .......................................... 157

Figure 5.9 Layer thickness of segregated fine aggregate for different resin volume fraction. ................................................................................................................................................. 158

Figure 5.10 Flexural strength of PC versus resin volume fraction. ..................................... 159

Figure 5.11 Time domain for different PC samples containing 13, 17 and 20% resin volume fraction. ................................................................................................................................... 160

Figure 5.12 Effect of the amount of resin polymer concrete on the structural damping system. ..................................................................................................................................... 161

Figure 5.13 CAD model of a CNC grinding tool machine and the base, in transparent mode, demonstrating insert supports using yellow arrows. .............................................. 162

Figure 5.14 Centroid determinations for each individual group of components (tagged by red)........................................................................................................................................... 163

Figure 5.15 The main mass point to be included in the simulation. ................................... 163

Figure 5.16 Outlet, inlet and environment temperatures versus time under operational conditions for a CNC grinder tool machine. ........................................................................ 164

Figure 5.17 Temperatures and the areas where they were applied on the base. ............... 165

Figure 5.18 Temperature distribution on the base of the CNC grinder tool machine....... 165

Figure 5.19 Structural deformations under thermal conditions (a) first composition (basalt, spodumene, and fly ash), (b) last composition (gravel, sand, chalk). ................................ 167

Figure 5.20 Structural deformations under thermal condition (a) PC resin amount 17% (b) PC resin amount 13%. ............................................................................................................ 167

Figure 6.1 Experimental setup for measuring the frequency and the amplitude of a vibrating table. ........................................................................................................................ 173

Figure 6.2 Relation between the amplitude and set frequency for the vibration table. .... 175

Figure 6.3 The mould contains the PC sample mounted on vibration table, the frequency applied. .................................................................................................................................... 176

Figure 6.4 Temperature of MMA/ARAPOL resins with different content of DMA. ....... 179

Figure 6.5 Viscosity of resins versus their curing time for a variety of DMA content. ..... 180

Figure 6.6 Time to the maximum temperature of 40% ARAPOL/60% MMA resins with different contents of DMA for various moulding temperatures. ....................................... 181

Figure 6.7 DSC curves of 40%. ARAPOL/60%MMA resins without DMA (solid curve) and with 0.3% of DMA (broken curve). ................................................................................ 184

Figure 7.1 Moisture during the days of the week in aggregate used in polymer concrete. ................................................................................................................................................. 194

XVI

Figure 7.2 DSC data processing using the TA Specialty library: inset time of 70% conversion at 60 °C versus water content. ............................................................................ 196

Figure 7.3 Time of 70% conversion at 60 ℃ versus water content. ..................................... 197

Figure 7.4 Viscosity increase for UPE containing various amounts of water: inset gel time versus water percentage in UPE............................................................................................ 199

Figure7.5 FTIR spectra of polymeric matrix prepared with 0, 1, 2, 4 and 5%v initial water, (A) O-H and C-H stretching peaks, (B) C=O stretching peak and (C) the range including C-O and C-H bending. ........................................................................................................... 200

Figure 7.6 TGA of polymeric matrix containing various amounts of water. The inset show an expended region of water evaporation weight loss (the graphs are scaled up by 1% for clarity)...................................................................................................................................... 201

Figure 7.8 Mechanical properties of UP/S/MMA polymeric matrix as a function of water percentage; (A) Modulus of elasticity, (B) Tensile strength versus, (C) Flexural strength versus water percentage, (D) Tensile strength. .................................................................... 203

Figure 7.9 SEM images for flexural fracture resin containing different amounts of moisture; (A) moisture 1%, (B) moisture 3%, (C ) moisture 5%. Scale bar is 10 µm for all images...................................................................................................................................... 204

Figure 7.10 Half sphere void exhibiting the nature of a void inner surface for polymeric matrix fracture (scale bar is 1 µm). ........................................................................................ 205

Figure 7.11 Voids forming due to water existence at the early stage of curing resin containing 5% moisture. ........................................................................................................ 205

Figure 7.12 DMA analyses (A) storage modulus of polymeric matrix versus frequency (B) tan δ versus frequency for different water percentage. ....................................................... 207

Figure 7.13 Coefficient of thermal expansion (CTE) of polymeric matrix verses water percentage. .............................................................................................................................. 208

Figure 7.14 Flexural strength of polymer concrete composite system versus the percentage of moisture contents. .............................................................................................................. 209

Figure 7.15 Water distributions on a polymeric matrix and the interfacial bonding of matrix – aggregates in a polymer concrete composite system. ........................................... 211

Figure 7.16 PC sample containing 5% moisture. .................................................................. 211

Figure 7.17 Compressive strength of polymer concrete composite system verses the percentage of water content................................................................................................... 212

Figure 7.19 CTE of the PC composite system versus water content .................................. 214

Figure 8.1 Flexural strength of the PC as a function of maturing time at various maturing temperatures: ambient, 5 °C, 35 °C and 50°C. ..................................................................... 223

Figure 8.2 Relative strength of PC as a function of maturing time at 50 °C. ...................... 224

Figure 8.3 revealed a relationship connecting k with the temperature. ............................. 225

XVII

Figure 8.4 Relative strength versus maturing time for 5°C maturing temperature (◊) experimental data and red curve predicted by the empirical formula. ............................. 226

Figure 8.5 Relative strength versus maturing time for 35°C maturing temperature (◊) experimental data and red curve predicted by the empirical formula. ............................. 227

Figure 8.6 Relative strength versus maturing time for 50°C maturing temperature (◊) experimental data and red curve predicted by the empirical formula. ............................. 227

Figure 8.7 Moisture 1%, increase the maturing temperature increased the cracks and voids in UPE resin binder. ............................................................................................................... 229

Figure 8.8 Moisture 2% shows a higher level of cracks and void populations in UPE resin binder. ..................................................................................................................................... 230

XVIII

List of tables

Table 2.1 Examples of some non-styrene monomers used in UPEs. .................................... 25

Table 2.2 Mechanical properties of polymer concrete, resin is MMA – TMPTMA at various temperatures (Kukacka, 1973). ................................................................................................ 28

Table 2.3 Different combinations of PET-to-glycol ratio, dibasic acids and initiator promoter for UPE made from PET waste (Mahdi et al., 2010). ............................................. 32

Table 3.3.1 UPE properties supplied by the manufacturer. .................................................. 65

Table 3.2 Styrene specifications provided by the manufacturer. .......................................... 66

Table 3.3 MMA properties provided by the supplier. ........................................................... 67

Table 3.4 MEKP properties provided by the supplier. .......................................................... 68

Table 3.5 Cobalt octoate supplier specifications in different concentrations. ..................... 69

Table 3.6 DMA Supplier specifications obtained from the supplier..................................... 70

Table 3.7 Specifications of basal obtained from the supplier. ............................................... 71

Table 3.8 Specifications of gravel delivered by the supplier. ................................................ 72

Table 3.9 Sand specifications obtained from the supplier. .................................................... 72

Table 3.10 chemical contents of spodumene obtained from the supplier. ........................... 73

Table 3.11 Fly ash specifications obtained from the supplier. .............................................. 74

Table 3.12 Chalk specifications obtained from the supplier.................................................. 75

Table 3.13 Resin chemical constituencies and volume fraction for each. ............................. 98

Table 3.14 Centre-to-centre distance of the supporting and loading roller for.................. 102

Table 4.1 comparison of the published data for epoxy and UPE with the optimized resin ................................................................................................................................................. 137

Table 5.1 Properties of all sizes of aggregates: coarse, middle and fine filler. ................... 141

Table 5.2 Aggregate average diameters and volume voids. ............................................... 142

Table 5.3 Ratios (K) of average smallest diameters to largest diameters for potential compositions. .......................................................................................................................... 143

Table 5.4 Intermediate generation for the compositions. .................................................... 145

Table 5.5 Total absolute volume of fillers for each composition. ........................................ 146

Table 5.6 Theoretical total volume fraction of solid for each composition. ....................... 147

Table 5.7 Volume fraction for each aggregate within its composition for all compositions. ................................................................................................................................................. 148

Table 5.8 Aggregate compositions used in the PC formulations in this study and their flexural strength and CTE. ..................................................................................................... 153

XIX

Table 5.9 Effect of PC composition, resin volume fraction on precision of the base ......... 168

Table 5.10 comparison of the published data for PC-epoxy based and PC-UPE based with the optimized PC. ................................................................................................................... 170

Table 6.1 The frequency and amplitude of the vibrating table. .......................................... 174

Table 6.2 Vibrating time and compressive strength of PC samples ................................... 177

Table 6.3 Recommended DMA content for different moulding temperatures. ................. 182

Table 6.4 Parameters of Borchardt and Daniels model for 40%ARAPOL /60%MMA resins with different contents of DMA. ........................................................................................... 184

Table 6.5 Mechanical properties of resins with different volume fractions of DMA. ....... 186

Table 6.6 Effect of mixing technology on flexural strength of PC. ..................................... 187

Table 7.1 Water solubility for polymeric matrix contents. .................................................. 193

Table 7.2 Parameters of Borchardt and Daniels model for different resin moisture contents. .................................................................................................................................. 198

Table 7.3 Peak temperatures for resins containing various amounts of water .................. 202

Table 7.4 BET analysis of all aggregates used in the composition of polymer concrete ... 210

XX

Contents

Statement of Authenticity……..……………….....……………………………………. II

Acknowledgements …..………………...……………………………………………….III

Publications....………………………………………………………………………….. IV

Abstract...……………………………………………………………………………….. V

Significant contributions…………………………………………………………….VIII

Abbreviations …………….…………………………………………………………....X

Symbols.....…………….…………………………………………………………......XI

List of Figures ………………………………………………………………………….XIII

List of Tables .................................................………………………………………. XVIII

Contents ...……………..…………………………………………………………….. XXI

Table of Contents ……..…………………………………………………………….. XXI

XXI

Table of Contents

1 Introduction ................................................................................................................... 1

1.1 Precision machines ........................................................................................... 1

1.2 Precision tool machines ................................................................................... 3

1.3 The effect of level of precision tool on product accuracy in manufacturing

sequence ...................................................................................................................... 6

1.4 Bases for precision machines ........................................................................... 8

1.5 The replacement of cast iron by polymer concrete for bases of precision

tool machines: advantages and disadvantages ...................................................... 10

1.6 Research objectives......................................................................................... 13

1.7 Dissertation outlets ........................................................................................ 14

Chapter 2 Literature review ........................................................................................... 18

2.1 Introduction .................................................................................................... 18

2.2 Thermosetting material in polymer concrete ............................................... 19

2.3 The use of thermoset material in polymer concrete research ..................... 20

2.3.1 The use of thermosetting binder in manufacturing PC base precision

tool machine ........................................................................................................... 22

2.3.2 Unsaturated polyester and copolymers ................................................ 23

2.4 Polymer concrete containing UPE-MMA as a resin binder ........................ 28

2.4.1 UPE produced from recycled PET used as a binder in PC .................. 29

2.4.2 Improve the damping properties of UPE polymeric matrix ............... 33

2.4.3 Effect of curing on mechanical properties of UPE ............................... 34

2.5 Fillers in polymer concrete ............................................................................ 35

XXII

2.5.1 Effect of fillers on polymer concrete properties ................................... 35

2.6 Properties of polymer concrete composite system ...................................... 39

2.6.1 Maturity and long-term properties of polymer concrete ..................... 48

2.7 Polymer concrete for manufacturing the bases of precision tool machines

54

2.8 Conclusion ...................................................................................................... 60

Chapter 3 Materials and Methods ................................................................................. 64

3.1 Polymeric matrix ............................................................................................ 64

3.1.1 Unsaturated polyester (UP) .................................................................... 64

3.1.2 Styrene...................................................................................................... 65

3.1.3 Methyl methacrylate (MMA) ................................................................. 66

3.1.4 Methyl Ethyl Ketone Peroxide (MEKP) ................................................ 67

3.1.5 Promoter .................................................................................................. 68

3.1.6 Accelerator ............................................................................................... 69

3.2 Specifications of filler composition of polymer concrete ............................ 70

3.2.1 Basalt ........................................................................................................ 70

3.2.2 Gravel ....................................................................................................... 71

3.2.3 Sand .......................................................................................................... 72

3.2.4 Spodumene .............................................................................................. 73

3.2.5 Fly ash ...................................................................................................... 73

3.2.6 Chalk ........................................................................................................ 74

3.3 Methods of measuring properties of fillers .................................................. 75

3.3.1 Sieve analysis ........................................................................................... 75

3.3.2 Determination of the particle size distribution using laser scattering 76

3.3.3 Bulk density ............................................................................................. 78

3.3.4 True density ............................................................................................. 79

XXIII

3.3.5 BET (Brunauer, Emmett, and Teller) surface area ................................ 79

3.3.6 Method of measuring aggregate moisture content .............................. 79

3.4 Methods of testing polymeric matrix ........................................................... 80

3.4.1 Methods of testing mechanical and thermal properties for polymeric

matrix 80

3.4.1.1 Methods of testing tensile and flexural strength .............................. 81

3.4.1.2 Hardness (Shore D Test Method) ....................................................... 82

3.4.1.3 Coefficient of thermal expansion (CTE) for the resin ....................... 82

3.4.1.4 DMA analysis....................................................................................... 85

3.4.2 Rheological analysis ................................................................................ 87

3.4.2.1 Measurement of viscosity growth during polymerisation .............. 88

3.4.2.2 Method of monitoring resin temperature profile during

polymerisation. ................................................................................................... 89

3.4.2.3 Method of measuring gel time ........................................................... 91

3.4.3 Thermal analysis ..................................................................................... 91

3.4.3.1 Differential Scanning Calorimetry (DSC) .......................................... 91

3.4.3.2 Thermal Gravimetry Analysis (TGA) ................................................ 94

3.4.4 Scanning Electron Microscopy (SEM) ................................................... 95

3.4.5 Fourier Transform Infrared Spectroscopy (ATR-FTIR) ....................... 95

3.5 Methods of testing polymer concrete composite system ............................ 96

3.5.1 Sample preparation for polymer concrete composite system ............. 96

3.5.2 Compressive strength ........................................................................... 100

3.5.3 Flexural strength ................................................................................... 102

3.5.4 Measuring the structural damping ratio for a system containing 85-

90% polymer concrete.......................................................................................... 105

3.5.5 Measuring coefficient of thermal expansion (CTE) for PC composite

110

XXIV

Chapter 4 Optimization of polymeric matrix ............................................................. 112

4.1 Introduction .................................................................................................. 112

4.2 Curing of unsaturated polyester resin........................................................ 113

4.2.1 Initiation step: ........................................................................................ 114

4.2.2 Propagation step: .................................................................................. 114

4.2.3 Termination step: .................................................................................. 115

4.3 Rheological analysis ..................................................................................... 117

4.3.1 The effect of styrene/UPE ratio ........................................................... 117

4.3.2 The effect of MMA/styrene/UPE ratio............................................... 119

4.3.3 Exothermic temperature ARAPOL/Styrene compositions ............... 121

4.3.4 Exothermic temperature ARAPOL/MMA compositions ................. 122

4.4 Mechanical properties .................................................................................. 123

4.4.1 Damping factor for polymeric matrix ................................................. 124

4.4.2 Flexural strength ................................................................................... 127

4.4.3 Tensile strength ..................................................................................... 128

4.4.4 Coefficient of thermal expansion (CTE) for polymeric matrix .......... 130

4.4.5 Hardness ................................................................................................ 134

4.5 Conclusions................................................................................................... 135

Chapter 5 Optimization of the polymer concrete filler composition system .......... 138

5.1 Introduction .................................................................................................. 138

5.2 Particles properties of aggregates ............................................................... 139

5.3 Thermal expansion of composite material ................................................. 149

5.4 Results and discussion ................................................................................. 151

5.5 Effect of resin volume fraction on polymer concrete damping ................ 159

5.6 Results validation ......................................................................................... 161

XXV

5.7 Conclusions................................................................................................... 168

Chapter 6 Optimization of moulding technology ..................................................... 171

6.1 Introduction .................................................................................................. 171

6.2 The effect of the number of voids on the compressive strength of polymer

concrete ................................................................................................................... 172

6.3 Identification of maximum moulding duration as a function of moulding

temperature and DMA content in resin binder ................................................... 177

6.3.1 Effect of DMA (promoter) contents on temperature rise during curing

178

6.3.2 Effect of DMA contents on viscosity growth during resin

copolymerization ................................................................................................. 179

6.3.3 Effect of DMA content on curing behaviour of resin binder ............. 183

6.3.4 Effect of DMA contents on resin binder mechanical properties ....... 185

6.4 Optimization of mixing technology of PC ................................................. 186

6.5 Conclusions................................................................................................... 188

Chapter 7 Influence of moisture on the thermal and mechanical properties and

curing behaviour of a polymeric matrix and PC composite system ........................ 189

7.1 Introduction .................................................................................................. 189

7.2 Sample preparation ...................................................................................... 190

7.2.1 Resin domain ......................................................................................... 190

7.2.2 Polymer concrete composite ................................................................ 191

7.3 Results and discussion ................................................................................. 192

7.3.1 Measuring the level of moisture in aggregate .................................... 193

7.3.2 Curing behaviour of the polymeric matrix ......................................... 194

7.3.3 Interaction of polymeric matrix with water ........................................ 199

XXVI

7.3.4 Thermal Gravimetric Analysis (TGA) ................................................. 200

7.3.5 Resin domain mechanical properties .................................................. 202

7.3.6 Dynamic Mechanical Analyses (DMA) ............................................... 206

7.3.7 Coefficient of thermal expansion (CTE) of polymeric matrix ........... 207

7.4 Mechanical properties of polymer concrete composite material ............. 208

7.4.1 Coefficient of thermal expansion (CTE) of PC composite system .... 212

7.5 Conclusions................................................................................................... 214

Chapter 8 Maturity studies of polymer concrete ....................................................... 216

8.1 Introduction .................................................................................................. 216

8.2 Maturity method .......................................................................................... 217

8.3 Datum temperature ...................................................................................... 220

8.4 Estimation of datum temperature............................................................... 220

8.5 Experimental studies of polymer concrete maturity ................................. 221

8.6 Relative flexural strength ............................................................................ 224

8.7 Moisture effect on the resin mechanical properties during maturing ..... 228

8.8 Conclusions................................................................................................... 231

Chapter 9 Conclusions ................................................................................................. 232

9.1 Introduction .................................................................................................. 232

9.2 Major Findings and Original Contributions .............................................. 233

9.3 Recommendation and Future Work ........................................................... 237

References...................................................................................................................... 239

1

Chapter 1

1 Introduction

1.1 Precision machines

A precision machine is a machine that performs a machining or non-machining

process on a workpiece to a very high tolerance. The tolerance depends on the

machine, the complexity of the workpiece and the stability of the work envelope.

Precision machines can be classified into two categories: cutting precision

machines and non-cutting precision machines. Precision cutting machines include

computer numerical control (CNC) grinding tool machines, CNC milling

machines, CNC turning centres, water jet cutting machines, laser cutting machines

and ultrasonic machining centres. Precision non-cutting machines include

magmatic resonance imaging MRI-machines, computerised tomography CT-

scanners and metrology machines. All precision machines require ultra-stability

for the workpiece envelope during operational conditions (Kim et al., 1995). Figure

1.1 shows a CT-scanner equipped with an enclosure made of polymer concrete

(PC) for radiation protection and a PC base to enhance precision by damping the

vibrations generated by the servomotors that control workpiece position and other

servomotors operating on the workpiece.

2

Figure 1.1 CT-3D scanner machine.

The levels of vibration load, mechanical and thermal loads vary in precision

machines, and depend on the precision machine’s functionality, capacity, stability

and product complexity (Ema and Marui, 2003). A simple measurement for overall

loads is the number of servo motors that a machine contains. For example, a CNC

grinder tool machine has 5-7 servo motors operating at various speeds and located

in different positions on the machine guided by 5 axes of motion, and in most

production conditions operating at high speeds. It has a greater level of vibration

compared to a CT-scanner, which contains only 2-3 servo motors operating at very

low speeds for the sole purpose of moving and locating the workpiece (patient).

The process of scanning 3-D images by CT-scanners would be more assured of

sharp image acquisition in a vibration-free condition. This would assist in accurate

patient diagnosis, and enable the scanning of non-patient work-pieces to the same

level of image acquisition, thereby providing accurate data. A high level of

accuracy can be achieved when the machine is equipped with a PC base. Here is

3

the magnitude of polymer concrete material used in the base of a precision

machine to damp the unwanted vibrations accompanied with the operational

condition to enhance the precision of the machine (Orak and Karademir, 2000).

1.2 Precision tool machines

The definition of a precision tool machine is elusive. There is no exact set of

tolerance ranges that clearly defines a workpiece allowance limit when produced

from a precision tool machine. A product considered high precision can range

anywhere from having to consistently maintain a 5-micron tolerance for a large

batch of parts, to maintaining a 2-micron, true positioning tolerance. This results

when two parts accurately match up with each other (Techspex, 2008). This figure

for understanding precision is not a constant level and can be changed depending

on the time and assignment. One of the best applications in a precision cutting

machine is the CNC grinding tool machine that evolved in terms of the precision

level in accelerated steps. The demand for precision in tools has grown to such

high levels to satisfy the growth in technology. This development has been

continuous because of advanced manufacturing technologies for applications in

the optical, automotive and communication industries, and especially in the

medical and life sciences fields (Park, 2008).

The accuracy of precision tool machines depends on the stability level of the

machine base-frame during operation. The stability level is affected by the

subsystems mounted on the base that holds the workpiece, as well as on other

subsystems that are responsible for conducting operations on a workpiece such as

the cutting tool subsystem. Figure 1.2 shows a CNC grinding tool machine

(ANCA, 2011). The positioning and cutting subsystems and their accuracy are

4

under complex dynamic and static internal loads in precision tool machines. These

loads are generated from servo motors and other machine components, where

forces, torques, vibrations and heat gradients are produced throughout the system

to satisfy the grinding operation requirements.

Figure 1.2 CNC grinding tool machine.

In the meantime, these loads act as an error source because of their share in the

thermal and dynamic stabilities in the workpiece envelope. Figure 1.3 shows the

arrangement of a grinding wheel and the workpiece (tool) during a grinding

operation. The machine has a special fixture that adds more stability to a relatively

long workpiece for the purpose of gaining a better surface finish, a high level of

precision and longer tool life (ANCA, 2009).

5

Figure 1.3 (A) The tool, (B) grinding wheel arrangement, the (C) spindle and the (C)fixture for more stability and more precision.

The main challenges for a CNC grinding tool machine are the geometric

complexity (Tunc and Budak, 2012) and the high level of product surface finish for

the workpiece, as these are vital precision requirements (Peter, 1965). Figure 1.4

shows tools with various geometries that can be manufactured by a CNC grinder

tool machine. To satisfy these requirements, a workpiece should have a high level

of stability throughout the manufacturing operation. The parameters affecting the

grinding operation in terms of precision are: the material of the produced tool, the

grinding wheel material, and the process control, such as the feed and speed of the

grinding wheel and the tool’s complexity. Each of these parameters influences the

precision level of the machine (Techspex, 2008).

6

Figure 1.4 Tools of different geometries that can be made with precision tool machine.

1.3 The effect of level of precision tool on product accuracy in

manufacturing sequence

A milling tool is a good example to demonstrate the effect of the level of tool

precision on product accuracy through a manufacturing sequence. Once a milling

tool is produced, it will then be used in a CNC milling machine to manufacture

other products. Some of the products can be considered as tools for manufacturing

a particular product. For example, a micro-injection mould (tool) can be used in

producing micro-gears (product), which can be used in micro-fluid pumps,

harmonic drivers, watches and medical equipment. Figure 1.5 illustrates the stages

in the manufacture of plastic micro-gears. Micro-plastic gears eliminate noise due

to the good damping properties of plastic. The noise was generated from the steel

gears that were previously used in such applications. Other advantages of plastic

gears are the ease of manufacture and the high productivity of the injection

moulding process, which are reflected in the product life cycle of the gears, their

high anti-corrosion resistance and precise control (Dopper et al., 1997).

7

Each process in the manufacturing sequence of the milling tool will have an

influential effect on the precision of the micro-injection mould. The accuracy and

functionality of the end product (for example, micro-plastic gears) will be affected

by the accuracy of the post-process levels of the milling tool. In this case, micro-

plastic gears inherit their level of accuracy from the original tool (milling tool)

through the process of manufacture of the micro-mould. This depends greatly on

the original milling tool produced by the CNC grinding tool machine and the

milling machine used for the milling the micro-mould. The level of accuracy of

both precision machines determines the accuracy level for all the products created,

and hence the importance of a PC base for both the CNC grinding tool machine

and the milling machine (Suh and Lee, 2008a). PC has a marked effect on the

precision of the milling tool by damping the unwanted vibration created by servo

motors during the manufacturing operation (Sezan, 2000).

Figure 1.5 Manufacturing the core of a mould, a micro mould for a plastic micro gear, and the steel micro gear.

8

1.4 Bases for precision machines

The bases for precision tool machines can be manufactured using different

materials, including cast iron, polymer concrete (Lee et al., 2004), ferrocement

(Rahman et al., 1987) and combined PC and ordinary concrete (Ding, 2010). The

traditional material used in the manufacture of a CNC grinding tool machine base

used to be manufactured using cast iron, but this did not fully satisfy the

requirements due to the low damping ratio of cast iron, the inflexibility of the cast

iron in terms of adapting internal plastic pipes, and the complexity in

manufacturing, especially after the casting process. Ferrocement concrete and

traditional concrete have a higher damping ratio than cast iron and PC has the

highest (Rahman et al., 2001). PC is a composite material comprised of two kinds

of constituents, namely well-graded inorganic aggregates and organic resin binder

(ACI, 1986). A wide range of diversified thermosetting resins used as a polymeric

matrix, namely epoxies, unsaturated polyester (UPE), polyureas, furan and

polyurethane (Mosiewicki et al., 2009). Potential thermosetting resins to be used as

a polymeric matrix in PC are including polysiloxanes, polyimides and polyglycols

(Bucknall, 1992). Epoxies exhibit high strength, low shrinkage, and a relatively low

coefficient of thermal expansion (CTE), and provide toughness as well as

resistance to chemical and environmental damage (Michel, 2007). Unsaturated

polyester provides excellent adhesive properties, a relatively lower strength than

epoxy, a higher CTE and higher shrinkage than epoxy (Fowler, 2003). A wide

variety of resins and aggregates has been used by various researchers to fabricate

PCs. Epoxy as a binder is still used in PCs, but substantial research and

engineering efforts have focussed upon cheaper vinyl monomers such as

unsaturated polyester resin, methyl methacrylates (MMA), furan derivatives and

styrene (Atta et al., 2005). There was a need for this research, which has optimized

the properties of the polymeric matrix according to the optimization criteria for

9

the base of precision tool machinery as most of the preceding research was

concerned with the resin as a material and did not connect the material fully with

the application. In this thesis, consideration has been given to both the material

and the application in order to reach the optimization.

Previous research on PC was more focused on the PC as a material and did not

address the optimization criteria for a particular application fully to enhance the

base of precision machine. There are some gaps, such as:

1. Optimization of the resin thermo-mechanical and rheological properties in

accordance with the manufacturing process of PC and the final structural

functionality of precision tool machine bases.

2. Nomination of the allowable moisture content in the fillers, based on the

influence of water on the mechanical, thermal and rheological properties of the

polymeric binder and the morphology of PC composite filler system.

3. Investigation of the effect of resin and filler volume fractions on the thermo-

mechanical properties that affect the precision performance of the grinding tool

machine. Investigation of properties such as CTE, damping characteristics and

mechanical strength of the PC composite system.

4. Investigation of the effect of moulding technology, including the

optimisation of mixing, maximum compaction and the vibrating time bias of the

10

rheological properties of the resin binder and morphological properties of the

filler.

5. Identification of the amount of DMA according to the temperature-time

dependant rheological properties of the polymeric binder and how it is going to

affect the mechanical properties of the resin and PC composite.

6. Nomination of the maximum allowable moulding period based on curing

studies and the temperature-time dependant, rheological properties of mortars.

7. Nomination of a maturing method compatible with the required

mechanical strength of the base according to the optimization criteria of the

grinding tool machine.

1.5 The replacement of cast iron by polymer concrete for bases of

precision tool machines: advantages and disadvantages

The PCs used for manufacturing the bases of precision machines have numerous

advantageous, including superior damping properties, manufacturing flexibility,

fast curing, and good mechanical properties including high flexural and

compression strengths. In addition, PCs have good adhesion for inserts, and are

corrosion-resistant as well as cost-effective. Consequently, PC is a perfect

replacement for cast iron (Bruni et al., 2008), which suffers from low damping

properties, high cost, and low chemical resistance (Salje and Gerloff, 1986). A

11

comparison of the properties of these materials and how they affect the

manufacturing process and machine performance is discussed below:

Damping ratio: PC has a higher damping ratio compared to other materials. Cast

iron has the lowest damping ratio compared to both PC and ordinary concrete

(Rahman et al., 2001).

Flexibility: Hydraulic fluid (plastic pipes), tanks, threaded and non-threaded

inserts, cutting fluids and conduit piping can all be integrated into a PC or a

concrete base. Incorporating multiple components into one casting has a great

impact on the reduction of assembly time. Multiple plastic components cannot be

included in one casting of cast iron because the casting temperature is higher than

the melting temperature of most plastic components (Salje and Gerloff, 1986).

Melting temperature: Cast iron requires a melting temperature of 1100 °C prior to

casting and machining after casting. PC does not require any temperature rise

during the process and no machining is required after curing.

Cost: PC and reinforced concrete materials are more cost-effective than cast iron as

they contain 80-87% low cost aggregates (Chang and Stephens, 1975).

Environmentally friendly: PC and reinforced concrete bases do not require as

much consumption of energy (Haddad et al., 1983) as cast iron for casting the base.

12

Chemical corrosion resistance: PC offers chemical resistance to most common

solvents, acids, alkalis and cutting fluids. Cast iron and conventional concrete are

susceptible to chemical corrosion under chemical attack (Gorninski et al., 2007).

Stiffness: PC has greater stiffness than concrete, and lower mechanical properties

than cast iron (Cortes and Castillo, 2007), making it highly acceptable for the base

of precision tool machines and fulfilling the application requirements.

Water permeability: PC has lower water permeability than cast iron and higher

permeability than concrete.

The disadvantages of PC and concrete when used for manufacturing the bases for

precision tool machines include the following:

High non-uniform thermal expansion: PC has a higher CTE because of the high

CTE of the resin binder (Valore and Naus, 1975), compared to cast iron which has

a low CTE. This condition leads to a non-uniform distribution of thermal

expansion for the base during operation that induces a high variation in

deflections on the base rails. This has a negative impact on the accuracy levels of

precision tool machines.

Low thermal conductivity: PC has a lower thermal conductivity than cast iron,

which has high thermal conductivity.

Creep and shrinkage: PC and reinforced concrete both have higher creep and

shrinkage than cast iron (Haque and Armeniades, 1985).

13

Maturing time: PC requires longer maturing time compared to cast iron (Lee et

al., 1997).

Machinability: Neither PC nor reinforced cement concrete can be machined, while

cast iron has high machinability.

Cost: PCs are more expensive than conventional concrete materials (Cortes and

Castillo, 2007).

1.6 Research objectives

The objectives of this research were as follows:

§ Optimisation of the polymeric matrix based on its rheological properties

and its mechanical and thermal characteristics. The optimization is in

accordance with the manufacturing process of PC and the structural

functionality of precision tool machine bases.

§ Identification of the acceptable moisture content in the fillers, based on the

influence of water on the mechanical, thermal and rheological properties of

the polymeric matrix and the PC composite system.

§ Optimisation of PC filler composition based on the manufacturing process

of PC and the structural functionality of precision tool machine bases.

Analysis of the effect of resin and filler volume fractions on the CTE,

14

damping characteristics and mechanical strength of the PC composite

system.

§ The material selection of the present research the was based on cost,

availability and the compatibility with the optimization criteria of PC

precision tool machines base. The results will be compared to each other in

accordance to the selection criteria, no need for benchmarking to be

involved in result comparison.

§ Development of moulding technology, including the optimisation of

mixing and maximum compaction. Identification of maximum allowable

moulding time based on curing studies and the temperature-time

dependant rheological properties of mortars.

§ Implementation of a maturing method, and determination of the

interdependencies between flexural strength, curing time and temperature.

§ Identification of the maturing time of PC and its dependence on

environmental conditions.

1.7 Dissertation outlets

This thesis contains nine chapters as follows:

Chapter 1 – Introduction: This chapter includes an overview of precision

machines, including precision tool machines and milling machines; how PC bases

15

have an essential role in the level of product accuracy; the inherited level of

accuracy when the product of a precision tool machine is used in producing

another product; and the advantages and disadvantages of the different kinds of

materials used in manufacturing bases, such as PC and cast iron. The research

objectives are also included in this chapter.

Chapter 2 – Literature review: This chapter contains a review of the relevant

research and information about the properties of PC composite material in terms

of binding resins and fillers, as well as a review of the use of PC in the

manufacture of bases of precision machines such as CNC grinder tool machines.

Chapter 3 – Materials specifications and testing methodology: This chapter

describes the experimental procedures, experimental set-up, the sample

preparation methods and material specifications used in this research.

Chapter 4 – Optimisation of polymeric matrix: In this chapter the optimal

chemical composition of the mortar is identified using resin’s thermal, mechanical

and rheological properties as criteria of optimization. The manufacturing process

and structural functionality of a precision tool machine base is also considered to

categorise the optimization criteria.

Chapter 5 – Optimization of polymer concrete composition: In this chapter,

various compositions of fillers (basalt, river gravel, spodumene, sand, fly ash, and

chalk) are tested and the results discussed. The outcomes are compared with the

16

guidelines for optimization criteria in terms of the mechanical and thermal

properties of the PC composite system. The preliminary optimum composition is

identified. However, the second in the rank of PC composition is nominated for

further optimization because of its volume fraction of filler and matrix. The final

optimized composition is nominated, and validation of the final composition for

the base of precision tool machines obtained. The validation reveals the effect of

the aggregates composition and resin volume fraction of a PC composite on base

behaviour, with regard to the accuracy level of the precision tool machine.

Chapter 6 – Optimization of moulding technology: This chapter shows how the

moulding technology of PC that has low voids population and reproducible

property is obtained. This includes the application of various frequencies during

the packing operation of a PC sample. The mechanical strength was tested for each

PC sample. The optimum vibration frequency to produce the PC sample that had

the highest mechanical strength was chosen. Three mixing technologies were

proposed and the optimum mixing technology nominated according to the level of

mechanical strength of the PC sample. The relationship between DMA amount

and moulding temperature and maximum moulding time is obtained, based on

the rheological analysis of the resin binder.

Chapter 7 – Influence of moisture on thermal and mechanical properties and the

curing behaviour of a polymeric matrix and PC composite system: This chapter

describes how different volumetric ratios of water were included in the initial

constituents of a polymeric matrix sample and water was induced in aggregates of

a PC composite sample. The mechanical and thermal properties of the matrix and

composite material of PC were tested, and the rheological behaviour of the

polymeric matrix was examined. It was found that the existence of water results in

17

weaker mechanical properties and a slower curing rate for the resin and PC

composite. The only property that improves is the resin damping factor as

moisture increase, which is a negligible improvement compared to the

shortcomings. The minimum limit for allowable moisture is identified. It is

concluded that eliminating moisture to the minimal amount is crucial in order to

maintain the quality and productivity of PC manufactured for precision tool

machine bases.

Chapter 8 –Polymer concrete maturity study: In this chapter, PC samples were

heated for various periods of time under different temperatures. PC samples were

tested for flexural strength with different maturity conditions. The maturity

method was identified and the datum temperature calculated. Mathematical

expressions that predict the correlation of the relative flexural strength with

maturing temperature as well as the time of maturing were evolved. It is

concluded that an increase in temperature by ten times decreases maturing time

by approximately 80%. The presence of moisture during the maturing process was

investigated. It was found that the existence of water diminishes the resin

mechanical properties by two or three times as the maturing temperature

increases, compared with the effect of moisture at the ambient temperature.

Chapter 9 – Conclusions and recommendations for further research: Finally, in

this chapter, conclusions and recommendations are drawn from this research. The

chapter also highlights the limitations and deficiencies and proposes further work

that could be undertaken to address these deficiencies.

18

Chapter 2

2 Literature review

2.1 Introduction

Polymer concrete (PC) is a composite material consisting of well-graded inorganic

aggregates bound using a resin instead of the water and cement binder typically

used in traditional cement concretes. The composite material of inorganic fillers

combined with a binding polymeric resin with a liquid organic resin which

hardens through the polymerisation reaction (Akihama, 1973; Andries, 1965; Ahn,

2004). Usually the binding resin is a thermosetting material curing irreversibly via

cross-linking by radical initiation (Gawdzik et al., 2003). The thermoset polymeric

binder in PC provides a matrix with high thermal, chemical and mechanical

stability, making PC the material of choice for use as high precision tool machine

bases.

19

2.2 Thermosetting material in polymer concrete

Thermoset is a polymeric material in which individual polymeric molecules have

been joined through covalent bonds in specific regions on the molecules. Covalent

bonds are generated by energetically exciting other polymeric molecules end

groups, specific functional groups or by use of monomers (Gawdzik et al., 2003).

The bonding of the molecules, also referred to as cross-linking, produces unique

behaviour, such as a thermal stability that is much higher than that of

thermoplastics. This condition arises because the rigidity of the macrostructure is

maintained through links between the polymers that oppose the flow of molecules

past each other. The mobility of molecules increases at higher temperatures due to

an increase in the energy levels in the molecules, which results in greater material

deflection. However, being one big macro-molecule, flow is not possible (Brunelle,

2008). Generally thermoset is maintained well under the thermal loads, the less

notable are the reductions in mechanical properties due to any temperature

increase. Other unique characteristics that make thermosets very attractive for

many applications include their bonding capabilities, their strength, their thermal

and damping characteristics, their chemical stability and minimal creep (Sidney,

1986). These physical and chemical properties rely on the processing conditions

and on the cross-linking curing reaction that takes place during the process

(Hanemann et al., 2010).

Thermoset material is used in a variety of applications such as paints and

adhesives, and in the automotive, building and packing industries, among others.

Thermosetting resins have been employed in this research project as a binding

resin in PC in order to examine the mechanical, thermal and rheological properties

of PC and the resin.

20

2.3 The use of thermoset material in polymer concrete research

The unsaturated polyester (UPE) resin used as a binder contain cyclohexanone

peroxide as a catalyst and cobalt naphthaenate as an initiator (Strarmenov et al.,

1965). A combination of methyl methacrylate (MMA) with UPE was also used in

PC to examine PC’s mechanical properties (Slomatove, 1970). UPE was also

utilized with MMA and terimethylol propane terimethacrylate (TMPTMA) as a

binder in PC and tested for different mechanical properties at elevated

temperatures.

A combination of UPE–MMA-styrene thermosetting resins was employed as a

binder for the purpose of testing the mechanical properties of PC (Burleson, 1974).

UPE was also used as a binder for PC where methyl ethyl ketone peroxide (MEKP)

was the catalyst and cobalt octoate was the promoter (Ohama, 1973). In another

study, PC containing poly-MMA-styrene resin was utilized to examine PC’s

mechanical properties (Chang and Stephens, 1975). An investigation into the

stress-strain relationship of PC containing UPE compared with two epoxies was

conducted to examine the properties of PC containing different resin binders (El-

Hawary and Abdel-Fattah, 2000). UPE was employed in another investigation in

order to induce additives such as a silane coupling agent, TMPTMA, and divinyl

benzene, which improved the properties of PC (Gorninski et al., 2004). UPE was

also utilized to study the effect of mortar types (orthophtalic, isophtalic) on the

strength degradation of PC in acidic environments (Dharmarajan, 1987, Gorninski

et al., 2007).

21

It is interesting to explore the usage of UPE in PC when combined with various

constituents and their effect on different aspects of PC’s mechanical, thermal and

chemical properties. It is also important to consider other polymers involved as a

thermosetting binder in PC, such as furfural-acetone and ureaformaldehyde. A

combination of furfural (F) and furfural-acetone (FA) monomer (Andries, 1965)

was employed as a mortar in PC, the proportion of F-FA being 1:7. In another

study, furfural acetone (FA) was used as a resin binder (Davydov, 1972 ) and the

PC’s mechanical properties examined. Elsewhere, furan resin was utilized as a

resin binder in PC (Muthukumar and Mohan, 2004). In Alzaydi et al.’s (1990)

study, ureaformaldehyde (UF) was utilized as a binding resin in PC to reduce the

cost of PC which is the resin. It was concluded that the compressive strength of

Portland cement concrete specimens is surpassed by that of ureaformaldehyde

(UF)-PC for a similar binder volume fraction (ALZAYDI et al., 1990).

Another study used UPE produced from recycled PET, which makes it more

attractive in terms of cost (Rebeiz 1996). The mechanical properties of PC

containing UPE produced from recycled PET are lower than those for UPE made

from virgin material. The UPE produced when using recycled PET may become

suitable for manufacturing the PC base, if the application requirements is fulfilled

by justify the structural design of the PC base and the aggregates composition of

the PC towards fulfilment of the application requirements such as low CTE and

high damping ratio, and this is a subject to future research outcomes. Structural

wise it is suitable for manufacturing the PC base other related parameter need to

be researched. It is also suitable for a construction application since it

demonstrates a higher level of mechanical strength than conventional concrete.

22

Numerous researchers have investigated different kinds of epoxy resins as a

binder for testing the mechanical and chemical properties of PC. Epoxy was used

as a mortar in various proportions of epoxy resin to PC (Welch et al., 1962) to

investigate its effects on the mechanical properties of PC. Epoxy was also

employed as a binder in PC, where creep studied , and a mathematical model was

developed to describe the creep behaviour in PC containing epoxy as a binder

(Broniewski and Jamrozy, 1975). Other researchers have utilized epoxy as a binder

in PC, investigating the effect of environmental temperature and NaOH

concentration on corrosion behaviour, and the corrosion mechanism of epoxy and

UPE in NaOH solution (Hojo et al., 1986, Reis, 2010). The effect of three

freeze/thaw thermal cycles for 7 days on the strengths of the optimized PC was

investigated experimentally and epoxy was used as the resin binder to find the

level of thermal cycles which influence the mechanical properties of PC (Shokrieh

et al., 2011).

2.3.1 The use of thermosetting binder in manufacturing PC base precision

tool machine

A wide range of thermosetting resins can be used as a binder for the PC used in

manufacturing the bases of precision tool machines, namely epoxies (Lu et al.,

2006), unsaturated polyester (UPE), furan (Andries, 1965) and polyurethane

(Michel, 2007). The most common thermosetting binders in PC are epoxies and

unsaturated polyester. Epoxies exhibit high strength (Lau and Buyukozturk, 2010),

low shrinkage, low coefficient of thermal expansion (CTE), and provide toughness

as well as resistance to chemical and environmental damage in comparison to UPE

(Kim et al., 1995).

23

Unsaturated polyester (UPE) provides good adhesive properties, relatively lower

strength, a higher coefficient of thermal expansion and higher shrinkage than

epoxy (Fowler, 2003). In addition, UPE is less expensive than epoxy and when

MMA is involved in the composition of the resin, at the early stage the initial

viscosity is low compared to epoxy (Vipulanandan and Paul, 1990), providing

sufficient mixing to enhance the process of the aggregate-resin mixing. In addition,

PCs containing poly methyl methacrylate (PMMA) as a binder showed a high

modulus of elasticity (Mun and Choi, 2008) and a very low thermal coefficient of

expansion (Blaga and Beaudoin, 1985), making MMA a good candidate to control

and balance the rheological, mechanical and CET characteristics of the binding

polymer in PC. The cost effectiveness, the potentially good thermal, mechanical

properties and the good process for mixing aggregate and resin are the main

drivers for research into UPE/styrene/MMA monomeric composition. The main

function of thermoset material is the binding resin in the PC composite system for

use in the bases of precision tool machines. The main reason for optimization of

PC used in precision tool machine in this research is to elevate the precision level

by inducing enhanced mechanical properties resin binder in the PC according to

the application requirements. Also obtain a flexible and low cost manufacturing

process of the precision tool machine PC base for further enhancement to the

mechanical strength.

2.3.2 Unsaturated polyester and copolymers

In general, the UPE structure varies, being defined by the repetitive carbon-carbon

double bond between carbonyl groups. UPE polymers have a number of average

molecular weights within the range of 800-3000 units. A generalized

representation of the UPE chemical structure is shown in Figure 2.1.

24

OO

O

O

n

Figure 2.1 A Generalized chemical structure of unsaturated polyester molecule.

Styrene is another monomer used as it has the benefit of being low in cost. Styrene

polymerize very actively with UPE at room temperature, show a higher rate of

polymerization at elevated temperatures, and have low viscosity. Styrene’s

chemical structure is shown in Figure 2.2.

Figure 2.2 Styrene chemical structure.

Other applications utilise monomers that are used to induce the co-polymerization

of UPEs. Their applications are shown in Table 2.1(Sidney, 1986).

25

Table 2.1 Examples of some non-styrene monomers used in UPEs.

Monomer Application Applications

Methyl methacrylate (MMA) Enhanced weather resistance

Butyl acrylate (BA) Enhanced weather resistance

Butyl methacrylate (BMA) Enhanced weather resistance

Alpha methyl styrene (AMS) "Cooler" cure, reduced exothermal

Vinyl toluene (VT) Less volatility, higher flash point

Para-methyl styrene (PMS) Less volatility, higher flash point

Octyl acrylamide (OAA) Solid monomer, moulding compounds

Methyl methacrylate (MMA) is a low viscosity monomer, clear liquid that

polymerises with UPE as a result of cross-linking in the presence of an initiator

such as MEKP. Mixing MMA with UPE results in low viscosity resin at the early

stage of curing which is enhanced the mixing performance of resin with the

aggregates. In addition PC containing poly (methyl methacrylate) as a binder

showed high modulus of elasticity (Mun and Choi, 2008) and very low thermal

coefficient of expansion (Blaga and Beaudoin, 1985). It also induces additional

properties in PC such as fast setting and low temperature hardening (Ohama et al.,

1981, Paul et al., 1973), leading to potentially good mechanical properties in PC

bases containing UPE/MMA composition. Figure 2.3 shows the chemical structure

of MMA.

26

CH2O

CH3

CH3

O

Figure 2.3 Chemical structure of MMA (monomer).

When the initiator is added, a free radical is produced that can interact with the

UPE carbon double bonds (C=C) and styrene molecules as well as MMA, creating

new radicals (Gawdzik et al., 2003). These new free radicals can then react with

other C=C double bonds, propagating the reaction and creating junctions that will

result in a cross-linked network (Sidney, 1986). methyl ethyl ketone peroxide

(MEKP) was used as an initiator and dimethyl aniline (DMA) as an accelerator to

increase the curing rate (Gawdzik et al., 2003). Figure 2.4 shows the chemical

structure of MEKP and Figure 2.5 shows the chemical structure of DMA.

O

CH3

O

CH3

OH OH

Figure 2.4 Chemical structure of MEKP(initiator).

27

N

CH3 CH3

Figure 2.5 Chemical structure of DMA

Cobalt octoate can be used as a promoter to increase the activity of a given

initiator (MEKP). The promoter helps in the decomposition of the initiator,

delivering radicals at low temperatures by producing low-level activation energy

for radicals to start the cross-linking, and initiates quickly. Figure 2.6 shows the

chemical structure of cobalt octoate.

O

O-

O

O-

Co2+

Figure 2.6 Chemical structure of cobalt octoate (promoter)

28

2.4 Polymer concrete containing UPE-MMA as a resin binder

The addition of methyl methacrylate (MMA) to UPE has been investigated by

Slomatove (Slomatove, 1970). The following observations were made: the addition

of MMA to UPE provided an increase in weathering resistance, strength increased

with time, and increase in shrinkage occurred in the polymer concrete using an

MMA-UPE resin composition. The increase of shrinkage in MMA-UPE resin

composition is due to the high shrinkage of UPE. In another study, a highly

graded aggregate mixture with MMA-TMPTMA (terimethylol propane

terimethacrylate) monomer was successfully designed. The PC was cured at 163

°C and tested at different temperatures, and the results are shown in Table 2.2

(Kukacka and Depuy, 1974).

Table 2.2 Mechanical properties of polymer concrete, resin is MMA – TMPTMA at various temperatures (Kukacka, 1973).

Testing

temperature °C

Compressive

Strength Mpa

Split Tensile

Strength Mpa

Modulus of

Elasticity Gpa

Poisson’ Ratio

-15 170,91 10.4 42.05 0.24

70 135.135 9.86 36.4 0.23

190 97.21 9.45 30.61 0.22

It was concluded that environmental temperatures greatly affect the mechanical

properties of PC.

29

2.4.1 UPE produced from recycled PET used as a binder in PC

The purpose of utilizing polyethylene terephthalate (PET) waste is to reduce the

high cost of PC which derives from the resin, and to dispose of the waste. Rrbeiz

investigated the strength properties of PC made using UPE made of recycled PET

plastic (Rebeiz 1996). It was found that PC could develop 80% of its final strength

in one day, with a compressive strength of 90 MPa and a flexural strength of about

20 MPa. The PC did not demonstrate a great loss in strength when tested at high

temperatures, and remained quite strong in compression and flexure when

compared to conventional concrete. Another study with a similar purpose

investigated different parameters (Jo et al., 2008) such as strength and resistance

to the acid and alkali compounds of PC, measured using differing coarse and fine

aggregate ratios and resin content. It was found that the strength of PC made

using UPE produced from recycled PET and recycled aggregate increases with

increasing resin content. The stress–strain curves of PCs with 100% natural

aggregate compared to 100% recycled aggregate exhibited different failure

mechanisms. In relation to acid resistance, the polymer concrete at 9% resin was

hardly affected by the Hydrochloric acid (HCl), whereas the PC containing 100%

recycled aggregate showed poor acid resistance. Unlike acid, the contents of the

alkali compounds did not seem to attack the PC with 100% recycled aggregate, as

could be observed from the weight change and the compressive strength (Jo et al.,

2008).

In a study conducted by Jo et al, both short-term and long-term creep models were

developed incorporating various types of filler (CaCO3 and fly ash) (Jo et al.,

2007). The difference between the proposed model and the experimental long-term

creep compliance was less than 4%. The creep strain in the early stages increases in

PC more rapidly than in ordinary concrete. The creep strain of PC without filler

30

was much higher than that of PC with filler CaCO3, which was more effective

than fly ash. The creep values increased with an increase in applied stress,

although the values were not proportional to the stress ratio, because of the

nonlinear viscoelastic behaviours of recycled PET in polymer concrete (Jo et al.,

2007). This result is partially consistent with the results of (Mahdi et al., 2007),

specifically in relation to the effect of resin volume fraction on mechanical

strength.

In similar research, Reis (2011) utilized PTE as aggregate and the mechanical

properties were measured. The fracture properties of PC composites were

investigated by adding shredded PET as filler, employing UPE and epoxy as a

resin binder individually. Both resin binders (UPE and epoxy) were produced

from virgin material (Reis, 2011). Shredded PET was used as a partial substitute

for natural fillers. The ratios of induced PET in the PC filler composition were 5%,

10%, 15% and 20% by weight. It was observed that a reduction of a specific weight

resulted as the PET filler ratio increased. As the PET content rose through each test

series, the PC material became more ductile and showed less brittle failure. Any

level of shredded PET adversely affected the fracture toughness and elasticity

modulus in both epoxy and UPE mortars. This improvement occurred in the

fracture energy for both epoxy and UPE polymer mortars when shredded PET

aggregates were added to the mixture as a substitute for natural filler. This

substitution produced a PC composite with high energy absorption that could be

used for structures under dynamic and impact conditions (Reis, 2011).

(Mahdi et al., 2010) conducted another investigation with a similar focus where

parameters such as PET-glycol ratio, dibasic acids and initiator promoter

combinations were studied, and their effects on mechanical properties, such as the

31

compressive stress of the UPE produced from recycled PET were investigated. The

UPE produced by using recycled PET plastic waste was depolymerised through

glycolysis. The initiator promoter combinations used were methyl ethyl ketone

peroxide (MEKP) and cobalt naphthaenate (CoNp) in one group of sets, and

benzoil peroxide (BPO) and N, N-diethyl aniline (NNDA) in the other group, as

shown in Table 2.3. for each set. The compressive strength of resin and PC

produced with MEKP as the initiator is more than the compressive strength of

resin and PC produced with BPO initiator (Mahdi et al., 2010). The compressive

strength of resin as well as PC produced with a PET to glycol ratio of 2:1 is usually

more than that of 1:1. The resin and PC produced with a PET to glycol ratio of 2:1

used maliec and phthalic anhydride as diabasic acids and MEKP and CoNp as

initiator and promoter produced a high compressive strength. The split tensile

strength of PC is either equal or more than the tensile strength of the equivalent

grade of cement concrete. It was concluded that set numbers 1, 2, 5 and 6 were

better than the rest in terms of compressive strength, split tensile strength,

morphology of the material and thermal stability as shown in Table 2.3 for each

set. The compressive strength of resin and PC produced with MEKP as the

initiator is greater than the compressive strength of resin and PC produced with

BPO initiator (Mahdi et al., 2010). The compressive strength of resin and PC

produced with a PET-to-glycol ratio of 2:1 is usually more than 1:1. The resin and

PC produced with a PET-to-glycol ratio of 2:1 used maliec and phthalic anhydride

as dibasic acids and MEKP and CoNp as initiator and promoter produced a high

compressive strength. The split tensile strength of PC is either equal to or more

than the tensile strength of the equivalent grade of cement concrete. It was

concluded that set numbers 1, 2, 5 and 6 were better than the rest in terms of

compressive strength, split tensile strength, morphology of the material and

thermal stability as shown in Table 2.3 (Mahdi et al., 2010). These various results

are important for establishing future research for PC precision machine bases

32

employing UPE produced from recycled PET that may accommodate the

application requirements. The most important parameters that need to be

investigated are the damping ratio and CTE of the binding resin as well as the PC

composite system.

Table 2.3 Different combinations of PET-to-glycol ratio, dibasic acids and initiator promoter for UPE made from PET waste (Mahdi et al., 2010).

Set C hem ica l co m binations o f U PE m ade o f recyc led PET

1

2

G ro up – I D ibasic acid maliec anhydride and phthalic anhyd ride Initiator Benzoil p ero xide , promo ter N , N -d ie thyl an iline P ET -to-glycol ratio 1:1 P ET -to-glycol ratio 2:1

3 4

G ro up – II Dibasic acid maliec anhydride , Initiator ben zo il peroxid e P rom oter N , N -diethyl aniline P ET -to-glycol ratio 1:1 P ET -to-glycol ratio 2:1

5 6

G ro up – III Dibasic acid m aliec anhydride and phthalic anh yd rid e Initiato r methy l eth yl ke tone per oxide (M E KP) Prom oter cobalt naphthanate (C oN p) PE T-to-glycol ratio 1:1 PE T-to-glycol ratio 2:1

7 8

G ro up – IV Dibasic acid m aliec anhydride Initiato r methy l eth yl ke tone per oxide (M E KP) Prom oter cobalt naphthanate (C oN p) PE T-to-glycol ratio 1:1 PE T-to-glycol ratio 2:1

33

2.4.2 Improve the damping properties of UPE polymeric matrix

When a rubbery phase is introduced into a polymeric matrix, the mobility of the

rubber molecules enhances the dissipation of vibration energy in the resin domain

(Cherian and Thachil, 2003, Pachpinyo et al., 2006). Synthetic and natural rubbers

and elastomers in solid and liquid forms have been applied to improve UPE

damping properties. Rubbers such as natural rubber latex (NRL) (Pachpinyo et al.,

2006) and styrene-butadiene rubber (SBR) (Ray, 2008), and functional elastomers

such as hydroxyl terminated polybutadiene, epoxidized natural rubber, hydroxyl

terminated natural rubber, and maleated nitrile rubber (Cherian and Thachil,

2003) have been used to enhance UPE damping properties.

Polyoxypropylenetriamine (POPTA) was employed combined with temperature

during curing to optimize the damping factor and mechanical properties of UPE

(De La Caba, 1999). In addition polyhedral oligomeric silsesquioxanes (EA-POSS)

was used to improve the damping behaviour and other mechanical properties of

UPE (Gao et al., 2009). These modifications increased the toughness and tensile

strength of the UPE resin. The dissimilarity of the rubbery and resin phases results

in miscibility problems which researchers have attempted to solve using

copolymerizing terminal groups (Maspoch and Martinez, 1998) and dispersants

and solvents (Pachpinyo et al., 2006). Copolymers of UPE and polyurethanes

(Cherian et al., 2006), polyureas, polysiloxanes, polyimides or polyglycols also

produce resins with improved damping properties (Bucknall, 1992).

Butadiene as vinyl monomer has also been employed to modify UPE resin’s

mechanical properties for the purpose of improving the damping properties of

UPE (Rodriguez, 1993). Including a rubbery phase into a polymeric matrix of PC

base by inducing materials such as NRL and SBR could increase the CTE of the

resin binder. This may resulted into increase the CTE of PC base of precision tool

34

machine which has a negative impact on the accuracy level of the precision tool

machine.

2.4.3 Effect of curing on mechanical properties of UPE

Curing and processing conditions also have a significant effect on UPE mechanical

properties. The literature suggests that varying the resin curing rate via the curing

temperature or the initiation mechanism or post-curing heat treatment of the resin

affect the UPE damping properties (Liu et al., 2002).

Li et al. (2004) studied the effect of high temperature curing and post-curing heat

treatment on the micro-heterogeneity of UPE and its effect on its mechanical

properties (Li et al., 2004). Kim et al. (1995) used UV initiation curing UPE and

found that the type and the amount of photo initiator affects the level of

improvement in mechanical properties (Kim et al., 1995). Sanchez et al. (2000)

showed that the styrene ratio in the UPE pre-polymerization mixture affects the

phase continuity of resin after curing due to the limited miscibility of polystyrene

in UPE (Sanchez et al., 2000). This phase separation can be affected dramatically

by curing temperature (Zheng et al., 1988).

35

2.5 Fillers in polymer concrete

Fillers occupy 80-85% of PC and they form the mechanical properties of the PC,

depending on filler proportion, the morphology of the aggregate, the particle size

distribution and the mechanical and thermal properties of the fillers. Different

kinds of fillers are used for PC that can be classified as natural and non-natural.

The main purpose of investigating a single filler or group of fillers is to enhance a

single mechanical or thermal property or group of mechanical and thermal

properties in a PC. The most common combination of aggregates is basalt, river

gravel, sand and chalk (Ohama, 1979, Burleson, 1974, Atta et al., 2005). Fly ash has

been employed in PC as filler in various research studies, as it enhances PC’s

mechanical properties (Semiha and Cengiz 2011, Demirboga and Gul, 2003,

Varughese and Chaturvedi, 1996). Portland cement Type II has been used as a

filler in PC for the purpose of improving PC’s mechanical properties (Tolbert and

Hackt, 1979). Siliceous aggregates, ground chopped glass and graded round iron

have been included in PC as fillers (Brocard and Cirrode 1967). PET waste has

been utilized as a filler as a way of recycling this material effectively (Reis and

Carneiro, 2011). Trap rock was employed as a filler in PC produce a higher

strength PC than other types of aggregate and Type I cement enhances the

strength considerably when replacing gypsum (Helal, 1978).

2.5.1 Effect of fillers on polymer concrete properties

The filler have a great effect of mechanical properties of PC composite system

because filler morphology forms the interfacial bonding and the adhesive of

binding resin with aggregates. In addition the fillers morphological, thermal and

mechanical properties have an effect of PC thermal, mechanical properties. The

use of siliceous aggregates, ground chopped glass and graded round iron was

36

investigated as fillers for PC (Brocard and Cirrode 1967). It necessitated a higher

resin volume fraction of 15% due to an increase in the surface area of the

aggregates, a compressive strength of 85 MPa, a modulus of rupture 16.69 MPa, a

dynamic modulus of 28.24 GPa and a static modulus of elasticity of 18.24 GPa. The

coefficient of thermal expansion (CTE) was 22×10-6 °C-1. Shrinkage and water

absorption were minimal. The aggregates as filler have not been used since the

results demonstrated that the addition of non-natural aggregates failed to improve

the strength. Upon examining the results obtained when employing this group of

fillers, it was reasonable to claim that the those kinds of fillers are not suitable for

manufacturing a PC base for precision tool machine due to high CTE and low

mechanical strength.

Ohama (Ohama, 1979) conducted another filler study, four coarse aggregates were

used to prepare PC samples to be tested for compressive strength using UPE as a

mortar. Each sample showed different results for compressive strength when the

volume fraction of coarse aggregates was varied. It was found that increasing the

compressive strength of coarse aggregates tends to increase the compressive

strength of polymer concrete (Ohama, 1979) and that increasing the volume

fraction of coarse aggregates tends to decrease the compressive strength of

polymer concrete.

In another study, shrinkage-free PC was achieved by dispersing small amounts of

the mineral montmorillonite into the resin (Haque and Armeniades, 1985). It was

found that the resin interacts with the hydrated mineral, creating expansion forces,

which counteract epoxy resin shrinkage. It was concluded that the addition of

0.2% of montmorillonite or less produced shrinkage-free PC composite systems

with a flexural strength 30% greater than the corresponding conventional PC. A

37

higher level of montmorillonite content created PC systems that expanded upon

curing or generated hydrostatic pressure during a constant-volume cure (Haque

and Armeniades, 1985). Montmorillonite filler could contribute to a shrinkage-free

PC base, but it is not available in Australia, making montmorillonite quite costly.

In another filler-focused study fly ash was introduced to PC as fine filler, granite

was used as a coarse aggregate, and river sand was the middle-sized aggregate.

The binder was epoxy and PC properties such as cure time, flexural strength and

resistance to water absorption were compared with PC containing river sand

(Varughese and Chaturvedi, 1996). Flexural strength, curing time and resistance of

water absorption were measured for both the fly ash samples and the river sand

samples. It was concluded that fly ash could be used as a fine aggregate to

partially or fully replace ordinary river sand in PC systems. The flexural strength

of PC was improved as the fly ash weight fraction increased. PC containing fly ash

needed a slightly shorter time to cure than the PC containing river sand. When fly

ash was increased to just below 50%, water absorption was equal to that of PC

containing river sand (Varughese and Chaturvedi, 1996).

Rebeiz et al. (2002) conducted a further study, in which fly ash was investigated as

a replacement for sand in PC (Rebeiz et al., 2002). It was demonstrated that the

replacement of 15% by weight of sand with fly ash improves the compressive

strength of unreinforced PC cylinders by about 30% and the flexural strength of

steel-reinforced PC beams by about 15%. Other improvements in properties were

relatively minor and included the tensile bond strength of PC under thermal

cycling and the creep compliance of the PC under sustained loading. This may be

because fly ash achieves better workability than sand. The morphology of the

particles is fine and the spherical particles of fly ash provide the fresh PC mix with

38

improved lubricating properties. The use of fly ash may also produce optimum

packing conditions for the different ratios of sand and fly ash during casting, thus

resulting in a more homogeneous and compact final PC product. The replacement

of sand with fly ash did not have an impact on the shear strength of PC (Rebeiz et

al., 2002).

Sofi et al. (2007) investigated numerous aggregate compositions in an effort to

assess the effects of the inclusion of coarse aggregates and granulated blast furnase

slag into a polymer composite system (Sofi et al., 2007). The engineering properties

of inorganic PC (referred to by the authors as IPC) include the modulus of

elasticity, Poisson's ratio, compressive strength, splitting tensile strength and

flexural strength, which were then compared with organic polymer concrete

(referred to by the authors as OPC). All tests were executed according to the

relevant Australian Standards. It was observed that for an IPC density similar to

OPC-based concretes, the average compressive strengths of IPC for different

compositions were sufficiently close to the design strength, with a mean of 52.4

MPa. The difference between the splitting tensile and flexural strength of the IPC

mixes was approximately 2.0 MPa. An evaluation of the static modulus of

elasticity of the IPC mixes was compared predominantly with models reported for

higher strength concretes. It was found that, similar to OPC-based concrete, most

mechanical properties depend upon the mix design and curing method (Sofi et al.,

2007). The results reported for this research were considered by the researchers to

be preliminary to long-term experimental work in the field of IPC. The researchers

advised that further research would be carried out in future using mix

compositions, including coarse aggregates with or without granulated blast-

furnace slag to reinforce the validity of the research (Sofi et al., 2007).

39

Barbuta et al. (2010) investigated the effect of fly ash on compressive strength,

flexural strength and split tensile strength. The results showed that the influence

of fly ash and silica fume contents on the mechanical properties of PC containing

epoxy resin as a binder was positive (Barbuta et al., 2010). The filler improved the

mechanical characteristics of PC compared to that of polymer concrete without the

investigated filler. The effect of variations in the filler compositions (100, 150,

200%) of silica powder and variations in epoxy resin (10, 15 ad 20%) on the

mechanical properties of PC was investigated. Compressive, flexural and tensile

strengths were tested. PC samples with 15 and 20% epoxy resin and 200% filler

(15% fine silica powder, 25% medium size silica powder and 60% coarse silica

powder) had maximum mechanical strengths. The values of compressive, flexural

and tensile strengths were 128.9, 22.5 and 16.2 MPa respectively(Barbuta et al.,

2010).

2.6 Properties of polymer concrete composite system

Flandro (1960) initiated the research into providing an alternative material to

Portland cement in concrete as a paster, which is PC resin. Numerous mixes and

curing procedures were investigated, using polyester resin as a binder (Flandro,

1960). A modulus of rupture of approximately 5.515 MPa and a compressive

strength of 110.316 MPa were achieved with the optimum mix resin weight of

267.55 kg resin per cubic meter. Oven cured at 176.6 ºC. In a similar study, the

epoxy was used as paster in PC for various proportions of epoxy resin (Welch et

al., 1962). Different volume fractions of epoxy resin were sampled using ¾ basalt

to sand as an aggregate composition for PC. The best result was accomplished

with the epoxy resin at 15% volume fraction. A compressive strength of 76.87

MPa, and a modulus of elasticity of 32.267 GPa were achieved when cured at

40

ambient temperature for 28 days. PC using UPE resin as a binder has also been

studied (Strarmenov et al., 1965). The aggregate was fine silica and sand. The resin

volume fraction was 16 %, containing cyclohexanone peroxide as a catalyst and

cobalt naphthaenate as an initiator. The following results were obtained: the PC

was sampled using 7×7×7 cm cubic moulds, and cured for 3 days. The

compressive strength achieved was 117.6 MPa and the flexural strength was 33.8

MPa.

Knab (1969) studied the discrepancy of load rate on the behaviour of polyester

concrete studied for both the long and short term (Knab, 1969). A mathematical

model was developed for the purpose of predicting long-term deflection.

Significant deformation occurred under both long and short-term loading, which

indicated a limitation on the use of polymer concrete in construction. Another

study where the PC was composed of 7-8% FA monomer, 1.5-2% benzene acid, 55-

57% granite chippings, 24-25% quartz and 9-10% micro filler(Andries, 1965). The

following results were obtained from the experimental PC: specific weight was

2.19-2.5 g/cm3, compressive strength was 67.56-96.52 MPa and tensile strength

was 2.19-2.5 MPa. A temperature variation test for 300 cycles between -30°C and

80°C showed a reduction in compressive strength of PC 50%-40% and 80%-85% in

tensile strength. Based on those results the PC containing a combination of

furfural (F) and furfural-acetone (FA) monomers suitability for manufacturing the

PC base of precision tool machine is subject to the investigation of application

requirement such as CTE flexural strength and damping properties. The

compression strength and tensile seem to be acceptable. A particular modification

on the structural design of the frame and the PC base precision tool machine also

further reinforcement is required for the same purpose. This procedure is to

41

accommodate the high deflection in long and short term loading and low

mechanical properties of PC consist of FA as a resin binder.

Burleson (1974) investigated unsaturated polyester UPE–MMA-styrene

thermosetting resin as a binder for PC for different aggregate grading (Burleson,

1974). Various resin proportions were added to fire retardants, until the optimum

mix was reached. Samples were cured at room temperature for 24 hours. Fine

sand was used as aggregate and the compressive strength was 145 MPa. The

flexural tensile strength was 32.61 MPa and the flexural modulus of elasticity was

10.06 GPa. The resin weight percentage was 20%. Using a larger-sized aggregate

(maximum size 12mm) and 8.3% resin weight percentage, the compressive

strength was 47.118 MPa, the flexural tensile strength was 14.3 MPa and the

flexural modulus of elasticity was 19.02 GPa. It was concluded that the PC was

cost-effective because of the low percentage of resin, which is the most expensive

ingredient.

Ohama (1973) performed another investigation where the mechanical properties

of polymer concrete were examined. The binder used was UPE. MEKP was the

catalyst and cobalt octoate was the promoter. The mix design included a resin

weight of 22.5%, 29.1% of 5-20 mm gravel, 9.5% of 1.2-5 coarse river sand and

83.8% of fine sand. Samples were cured at room temperature for one day, soaked

with water for six days, and then left at room temperature for seven days. The

outcome was the same strength regardless of the curing condition. Compression

strength and split tensile strength were 98 MPa and 9.8 MPa respectively (Ohama,

1973).

42

Chang and Stephens (1975) conducted a study in which the mechanical properties

were investigated of PC containing MMA-styrene monomers, with sand and

gravel as aggregates, the focus of the study was the creep Type I cement was used

as filler. The optimum resin content was 9% weight percent. The curing took place

at room temperature for four hours. The highest compressive strength was 106

MPa, the flexural strength was 24.5 MPa and the split tensile strength was 10.755

MPa. Under 10-20% of compression strength, creep was measured. Creep

increased as the resin percentage increased. The increase of temperature also

increased the creep, particularly at 40°C the creep increased sharply. Below 40°C,

creep increased almost linearly with stress (Chang and Stephens, 1975)..

Another study by Suzuki (1975) used a fire test on PC containing UPE; the model

dimensions were 1.52 × 1.85 × 3.2 m. No fire retardant was added to the resin.

Wall and floor thicknesses varied between 8-3 cm, the fire load used was 13

kg/m2, which is less than average in an ordinary building. A temperature of 500°C

was recorded after 8.5 minutes, yet no structural damage occurred. Another fire

load was tried with 24 kg /m2. Tests resulted in some cracks occurring on the

surface of the wall, yet no collapse occurred. At a load of 35 kg/m2, heavy sooty

smoke was released. The temperature reached 1000°C after 9 minutes and the

walls caught fire. The model collapsed after 29 minutes. Introducing Dawsonite

fire retardant did not improve the fire resistance (Suzuki, 1975).

Flame resistance of PC has also been tested (Prin and Cubaud, 1977). The flame

was originally from a propane-oxygen burner with a discharge of 5m³/hr located

20 cm below the shell with a circular fan of 80 cm in diameter and a temperature

of 3000°C. The gel coat burned instantly and ten minutes later the concrete started

burning, but only above the flame. The silica aggregates decomposed but the face

43

opposite to the exposed surface did not heat up. After half an hour, the

temperature on the opposite face had risen to 10°C above the ambient

temperature. One hour later it accelerated to 30°C. As evident in the experiments,

resistance to flame was elevated and the heat propagation through the PC was

delayed. This research on fire was valuable since it provided a figure for a PC base

of a precision machine when under fire.

Hojo et al. (1986) investigated the effect of temperature and NaOH concentration

on corrosion behaviour; the corrosion mechanism of epoxy and UPE resins in

NaOH solution. Resins researched in this study were two types of epoxy: phenol-

A hardened with methyl-tetrahydrophlic (MTHPA), and epoxy using the same

base with 1.8-p-mentandiamne (MDA) as a hardener and isophthalic unsaturated

polyester. Epoxies and unsaturated polyester resins were immersed in NaOH in

different concentrations for different temperatures. It was found that epoxy resin

hardened with MDA demonstrated no degradation during the immersion because

of its stable crosslink. Epoxy hardened with MTHPA demonstrated a uniform

corrosion with the dissolution of the surface. Increasing the temperature increased

the corrosion penetration through the resin. PC containing UPE was corroded

with colour conversion and the resin surface softened like rubber (Hojo et al.,

1986). The rate of corrosion could be controlled by diffusion of the solution

through the resin surface. The corrosion mechanism was similar to the metal

corrosion. A formula for predicting the strength of resin after immersion was

developed, consisting of the effect of temperature and the concentration of NaOH

solution by applying the corrosion rate.

C. Vipulanandan and Eliza Paul (1990) studied the behaviour of epoxy and

polyester PC when applying various curing temperatures (22 and 120

44

°C)(Vipulanandan and Paul, 1990), and the influence of aggregate sizes and

distribution on the mechanical properties of PC when the strain rate was varied

between 0.01%-0.6% per minute. It was found that the gap-graded aggregates

produce polymer concrete with better mechanical properties. The behaviour of

both PC epoxy based and PC polyester based are definitely influenced by the

curing condition and testing temperature.

In another study by C. Vipulanandan and Eliza Paul (1993), they studied the

compressive and tensile properties of polyester polymer and polymer concrete

under various curing conditions, temperatures, and strain rates. The curing

temperature was varied from room temperature to 80°C. The strain rate was

varied between 0.01% to 60% strain per minute and the temperature between 22°C

and 120°C (Vipulanandan and Paul, 1993). It was concluded that the optimum

curing conditions for polymer and polymer concrete were different. The strength,

failure strain, modulus, and stress‐strain relationship of polyester polymer and

polymer concrete were also influenced by the curing method, testing temperature,

and strain rate to varying degrees. The influence of test variables on the

mechanical properties of polymer binder and polymer concrete was quantified.

Pre-treating the aggregates with a silane coupling agent further enhanced the

compressive and tensile strength of the polymer concrete. (Vipulanandan and

Paul, 1993).

Czarnecki, L. et al. (1999) investigated the thermo mechanical properties of PC

containing polyester and epoxy as a polymeric binder, and the statistical

evaluation of the heterogeneity of polymer concrete was presented. It was found

that a material model based on quadratic functions formed a suitable basis for the

optimization of polymer concrete (Czarnecki, 1999). A comparison analysis of the

45

material models of the two main types of polymer concrete, epoxy and polyester

concrete, was also conducted. The overall desirability function was then used as

the metric for the multi-criteria optimization of polymer concrete. This

optimization process was applied to several PC composites, including polyester

concrete with silica fume, highly-filled polyester concrete that reduces material

costs, and epoxy concrete with low flammability and combustibility. Experimental

validation of the results of the optimization process was also conducted. It was

found that compressive strength, flexural strength, and the modulus of elasticity

were almost the same for both polyester concrete, epoxy concrete and,

surprisingly, CTE. The research done for this thesis does not agree with these

results (Czarnecki, 1999).

While it is important to explore the literature in terms of the mechanical and

chemical properties of PC, it is also interesting to review the moisture effect and

how to deal with it in PC. Ahn (2004) performed an investigation in which the

mechanical properties of PC made with wet aggregates was improved (Ahn,

2004). Zinc dactylate (ZDA) and calcium dactylate (CDA) were each used as an

additive to the resins (two epoxies). The variables were the amount of dactylate

monomer and the aggregate conditions (wet or dry). The compressive strength,

flexural strength, workability, working time, and curing time were measured.

ZDA was found to improve the workability. The working time and CDA were

also found to improve the compressive and the flexural strength when the PC mix

had wet aggregates (Ahn, 2004).

The moisture sensitivity of UPE and acrylic PCs with commercial metallic

monomer powders have been evaluated (Ahn, 2006). PCs containing different

levels of these powders were investigated with respect to the properties of

46

hardened PC. The mix design was optimized for workability and strength,

depending on the resin viscosity, the intended use and the additional quantities of

the polymeric materials. The properties investigated included the compressive

and flexural strengths of hardened PC. These polymeric materials offer the

possibility of using wet aggregates in polyester and acrylic PC construction. It was

concluded, after conducting a number of experiments, that the resistance to

moisture was improved substantially with the addition of ZDA and CDA.

Aggregate at a 0.5% moisture level with the addition of 5.0% of ZDA

demonstrated an increase of 122% in the flexural strength and 50% in the

compressive strength. At a 0.5% moisture level and with the addition of 5.0%

CDA, increases of 38% in the flexural strength and 11.7% in the compressive

strength over the control were obtained for the MMA-based PC system. The

remarkable increase in strength indicates that ZDA and CDA may allow for the

possibility of using wet aggregates in PC construction (Ahn, 2006). This research

may be essential in a situation where wet aggregates are used in the manufacture

of a PC base. ZDA and CDA are both very costly to implement in a production

environment where it is necessary to reduce the cost of manufacturing PC bases.

Gorninski et al. (2004) examined the modulus of elasticity of PC compounds

manufactured using two types of binders: orthophtalic or isophtalic UPE

(Gorninski et al., 2004). The compositions used were selected from the available

literature on PC compositions. Based on those data, the polymer concentrations

used were 12% of orthophtalic UPE and 13% of isophtalic UPE by weight of dry

materials. Fly ash was used as filler and compositions with 8%, 12%, 16% and 20%

of ash by weight of aggregate were studied. Statistical analysis of the data

revealed that the type of resin and the concentration of fly ash, both individually

and in combination, have a significant effect on the modulus of elasticity of PC.

47

The effect of UPE type (orthophtalic, isophtalic) and micro- filler fly ash

concentration levels on the strength degradation of PC in acidic environments has

also been investigated (Gorninski et al., 2007).

Shokrieh et al. (2011) investigated the effect of three freeze/thaw thermal cycles on

optimised PC. The criteria for optimization were epoxy resin weight fraction,

chopped glass fibre and percentage aggregate size for the highest compressive and

flexural strength that gained. The effect of three freeze/thaw thermal cycles: 25 °C

to 30 °C (cycle-A), 25 °C to 70 °C (cycle-B) and -30 °C to 70 °C (cycle-C), applied for

7 days on the strengths of the optimized PC was experimentally investigated. A

comparison was made of the experimental results for the mechanical strengths

measured at room temperature. It was found that heating and cooling cycles did

not influence the compressive strength of the optimally-designed PC. On the other

hand, the bending strength was more influenced by exposing PC to thermal cycle-

B (Shokrieh et al., 2011).

Weena Lokuge and Thiru Aravinthan (2013) investigated the mechanical

properties of PC composed of three types of resin (polyester, vinyl ester and epoxy

resin) when combined with different proportions of fly ash and sand. Three types

of resin (polyester, vinylester and epoxy resin) were combined with fly ash and

sand to make the organic polymer concrete mortar (Lokuge and Aravinthan,

2013). The effect of the polymeric binder, sand and fly ash contents on the

compressive strength, flexural strength, split tensile strength, modulus of elasticity

and ductility of polyester, vinylester and epoxy resin based PC was investigated. It

was found that polymer concrete mortar can achieve compressive strengths in the

range of 90–100 MPa. Tensile strength was 15 MPa for vinylester based polymer

concrete. The results showed that polymer based filler materials are suitable for

48

both compression and tensile loading applications (Lokuge and Aravinthan, 2013).

The optimum proportions of fly ash for optimum compressive strength was 10%.

It was also concluded that the addition of fly ash as a filler material resulted in a

reduction in the amount of resin, and an increment in the compressive strengths

for PC with all the three types of resins. Ductility improved with decreasing fly

ash content for all the mixes of PC concrete. Therefore confinement methods need

to be addressed properly if PC with fly ash is to be used in structural applications.

Modulus of elasticity increased with increasing fly ash content for all the mixes of

PC concrete. Split tensile strength and flexural strength exhibited a decreasing

trend with an increase in fly ash content for all the mixes.

2.6.1 Maturity and long-term properties of polymer concrete

Long term properties of polymer concrete such as creep have a great effect on the

performance of the PC material. Understanding the creep behaviour and when the

creep stop or going to the minimum determine the time line for the mounting

process of the precision machine parts to commence on the PC base. Measuring

the creep under various loads will provide a figure of the suitable load to obtain

the minimum creep, literature suggested several measures under different kinds

of loads for PC containing various resin. There is a relationship between the

maturity and the creep. Increasing the maturity reduce the creep. Cirrode

investigated the creep under a compressive load of 19.6 MPa, creep did not

stabilised for 2.5 years with a strain of 1800 ×10-6 (Brocard and Cirrode 1967) for a

PC with epoxy binder. Two thirds of the stretch was reached in two months. The

nature of the creep strain was to increase in a non-linear fashion with the creep

stress.

49

Tolbert and Hackt investigated the viscoelastic nature of polymer concrete, using

an epichlorohydrin/bisphenol A-type epoxy as a thermosetting binder. The

composition of the aggregates was 60% river gravel, 30% sand and 10% Portland

cement Type II. Compression samples were tested for the linearity of viscoelastic

behaviour (Tolbert and Hackt, 1979). The effect of mass size on creep for the

determination of the specific creep compliance and the associated elastic modulus

was researched. The creep compliance was determined by the least squares curve

fitting of the experimental creep data. Collocation a numerical Laplace transform

inversion routine was utilized in developing the equation for the relaxation

modulus. It was found from the results of the superposition and creep tests that

the PC behaved in a viscoelastic fashion linearly at the lower s t r e s s

r e g i o n s (Tolbert and Hackt, 1979). Further test ing was essential to

character ise the degree of linearity throughout the material’s useable stress

region. It was noted that the behaviour of polymer concrete is similar to Portland

cement. The creep rate of epoxy PC is slightly higher and the values of the

relaxation modulus which were similar to Portland cement at the initial stage

(Tolbert and Hackt, 1979).

Howdyshell investigated the creep characteristic of polymer concrete. The resin

binder was UPE, and methyl ethyl ketone peroxide (MEKP) was the initiator

(Howdyshell, 1972). Stress-strain was measured and constructed using both

mechanical and electrical methods. The average compression strength was 88.94

MPa. It was observed that the stress-strain relationship started to be non-linear at

50% of the ultimate load. The average modulus of elasticity was 23.09 GPa. Creep

was experimented with three stress levels: 23%, 44%and 66% of compressive

strength for 1000 hours. Creep samples suffered from premature failure at a stress

strength ratio of 0.48 preceded by a sudden increase in creep rate, except for the

50

23% of compression strength samples that withheld for 1000 hours (Howdyshell,

1972). Ultimate creep strain to elastic strain was 1.23. Creep recovery was about

50% of creep strain and the compressive strength did not drop after 1000 hours for

23% creep load. It was observed that the creep deformation is sensitive to

temperature. In another study a compressive creep test on polymer concrete using

unsaturated polyester resin as a binder was conducted (Ohama, 1974 ). The

following equation was developed as an outcome of the experimental data

expressed below:

)1.2...(.......................................................................tBA

tec +=

Where ce is the creep strain A and B are arbitrary constants. A low stress to

strength ratio was used for the experimental set up, and the highest creep strain

was 0.18.

In another study on creep in polymer concrete. The creep caused by compressive

strength on epoxy based PC was investigated (Broniewski and Jamrozy, 1975). A

model was developed that describes the creep as shown in equation 2.2.

)2.2........(...........................................................................................

=btee ot

where b is arbitrary constants, et time dependent strain and e0 the initial strain.

Equation 2.2 can be used in a PC system with or without fibre reinforcement. An

attempt was made to describe the creep behaviour in UPE as well as epoxy based

polymer concrete. A triple superposition scheme was undertaken to develop a

constitutive equation for the forecast of long term creep in PCs (Dharmarajan,

51

1987). The investigation was done on the influence of stress, temperature and resin

content on the creep responses of the PC, minimising the data onto the preferred

reference state. By successfully minimising the data, it was made possible to

elaborate the creep compliance of PC systems as a product of different separate

features of time (t), stress (S), temperature (T) and resin volume fraction (V), such

as :

( ) )3.2(....................................................exp..,,,

++

−= VKtK

RTHmJVSTtJ vsr

Another serious attempt to predict the creep of polymer concrete was made. The

principle of time temperature equivalence was used to predict the long term creep

of polymer concrete (Khristova and Aniskevich, 1995). In another study, the

physical aging of the polymer binder was seen to influence the creep of polymer

concrete. To predict the long-term creep accounting for the aging process, the

result of the experimental study of UPE resin-based concrete and its structural

components (an unfilled resin and a resin filled with diabasic flour), a function of

the time–temperature–aging time reduction was applied. It was found that the

changes in the creep compliance of the material followed according to the

principle of the time–aging equivalence, with the reduction function dependant on

the aging temperature (Khristova and Aniskevich, 1995).

Chen and Liu conducted a study on different parameter that effect the creep of PC

which is thermo-moisture creep of polymer concrete under compressive load

utilizing time-temperature-moisture analogy (superposition) for a short term (10

hours) (Chen and Liu, 2005). The temperature and moisture contents were

constants during the test. A model for the creep behaviour of PC was created

52

which has the ability of to predict the creep by knowing the temperature and

moisture environment.

In another study by Tolbert and Hacket, a group of parameters were investigated

in an effort to understand how a variation of a specific parameter could affect the

compressive strength (Tolbert and Hacket, 1976). Parameters included were:

polymer loading, catalyst, exothermic reaction, aggregate type, graduation and

moisture content, curing age, aggregate additives and Portland cement.

Epichlorohydrin bisphenol A-type epoxy resin was used as a thermosetting

binder. It was found that the type of aggregate affects the compressive strength.

The optimum amount of diethylenetriamine catalyst for maximum compressive

strength was near 10%. Levels of catalyst between 8 to 12 % provided acceptable

results. By reducing the amount of catalyst, the exothermic temperature of the

mixture could be reduced. The use of moist aggregate reduced the compressive

strength substantially, my research agreed with the moisture effect on

compressive strength. The use of Portland cement as an additive could negate the

majority of this reduction (moisture effect) when added in the proper quantity.

The curing period beyond 7 days affected the compressive strength, although the

increase in curing period had a significant effect on compressive strength.

While it is interesting to explore the literature of long term properties of polymer

concrete and the key parameters that were studied, it is also essential to consider

maturity and how it effects on the mechanical strength of PC. In a study about

maturity, the strength development of polymer concrete through different

maturing environments was investigated (Ohama and Demura, 1982). Polymer

concrete samples were prepared and cured in various conditions. The compressive

strength was then measured for the cured specimens. It was found out that the

53

optimum maturation time before an elevated maturing temperature for the resin

concrete was about 10 hours. A water cure was found to be applicable and was

damage-free for polymer concrete using unsaturated polyester as binder. The

maturity method of PC using UPE as a mortar and how to implement the gaining

of high compressive strength was investigated (Lee et al., 1997). The key controls

of the maturity study were identified, namely catalyst, accelerator and

temperature, as a function of curing time and compressive strength. Polymer

concrete samples were prepared and cured at different temperatures with a

variety of accelerators and catalyst contents, and then the compressive strength

was measured for each case. Maturing temperature-compressive strength

relationships were built and the datum temperature was estimated. It was

concluded that the datum temperature for maturity equations for polymer

concrete with different combined catalyst and accelerator contents could be

estimated using temperature–compressive strength relationships. The

compressive strength of polymer concrete could be forecast by using the following

equation:

)4.2.....(..................................................)]........logexp(1[ MpcBAc −−+=σ

where σc is the compressive strength of polymer concrete that is measured by

MPa. pM is the maturity of polymer concrete A, B and C are constants. Maturity

of polymer concrete is represented by the following equation:

( ) )5.2.....(................................................................................0 tTTM p ∆−=

54

Where T is the maturing temperature (°C) of polymer concrete. ( )0T is the datum

temperature (°C) below which polymer concrete does not gain any compressive

strength (Ohama and Demura, 1982).

Maksimov, R. D. et al. (1999) studied the creep of PC under compression load. The

formula of the concrete was established using an experimental-calculation

approach, and by using this method a highly compacted filler composition was

obtained (Maksimov et al., 1999). It was found that the compressive strength was

high under prolonged compression loads. The polymer-concrete also exhibited

noticeable creep behaviour with a linear relation between the creep strains and

stresses. After the action with half the ultimate load of over 3000 h, the total strains

exceed the instantaneous ones by 2.0 to 2.2 times. An accumulation of irreversible

strains was also observed, although their contribution to the total strain was small.

It was concluded that the stress-strain relation can be represented by the equation

of linear hereditary creep theory (Maksimov et al., 1999).

2.7 Polymer concrete for manufacturing the bases of precision

tool machines

McKeown and Morgan (1979) wrote the first engineering article describing the

benefits of using PC containing granite as aggregate and epoxy as a thermosetting

binder to produce precast components for items such as the bases for precision

tool machines. The comparison of PC, cast iron and granite was detailed in terms

of mechanical properties such as high damping factor, dimensional stability and

reasonable rigidity. Another benefit of PC is the manufacturing process compared

to cast iron. It was found that cast iron is not easy to handle and is costly, and

needs further machining. PC pre-casting has ease of manufacture, feasibility, and

55

the ability to embed plastic pipes. PC also costs less than cast iron (McKeown and

Morgan, 1979).

Morgan and McKeon (1979) compared mechanical properties of materials used to

manufacture precision tool machine bases (Morgan and McKeon, 1979). Several

materials were involved in this comparison, including cast iron, hydrolytic

concrete, mild steel, granite and PC. The comparison of the materials was in terms

of their properties, including the modulus of elasticity, specific stiffness, damping,

long-term dimensional stability, coolant resistance, wear rate, frictional properties,

thermal conductivity and lead time for manufacture. It was concluded that each

material compared had limitations. PC containing epoxy as a resin binder seems to

have most advantages compared to most of the reviewed materials for a machine

tool structure. Other advantages of PC are that it can be cast to size quickly and

precisely, it is low-cost, has a short manufacturing lead-time, high damping ratio,

and high stiffness. It is unaffected by coolants and is stable dimensionally.

Kim et al. (1995) studied the properties of PC for a machine tool base using epoxy

(IPCO 410) as a mortar. Numerous experiments were conducted to obtain the best

properties of PC for the application. The modulus, compressive strength, flexural

strength, CTE, specific heat, thermal conductivity, and damping factor were

measured by varying the compaction ratios, sizes and ingredients to assess the

effect of the processing parameters on PC properties. It was found that the optimal

compaction of PC was obtained when the pebble weight fraction was 55.5%. The

Young’s modulus and compressive strength increased, as the pebble weight

fraction increase for overall aggregate weight was constant in PC composite

systems. The Young’s modulus, compressive strength and flexural strength

increased as the resin content increased, as well as the CTE. When the resin weight

56

fraction was 7.5%, the CTE of PC was the same as that of cast iron (Kim et al.,

1995).

Orak (1999) investigated the usability of polymer concrete in the manufacture of

machine tool beds. The research was involved in damping characteristic of PC. PC

samples were prepared with equal amount of UPE resin and different quartz

material ratios were used in order to investigate (Orak and Karademir, 1998)

changes in the damping characteristic with structure. Damping experiments were

conducted using PC and cast iron samples for compression purpures. Critical

damping ratios were calculated with the free vibration method. It was observed

that the critical damping ratio of polymer concrete was approximately 4-7 times

higher than that of cast iron.

Other research in which a hybrid PC base for high-speed CNC milling was

designed and manufactured was conducted by (Suh and Lee, 2008b). The base

was composed of PC and welded steel structure faces. The dynamic characteristics

of the resin (unsaturated polyester) and the main aggregate (granite) were

measured by impulse dynamic tests according to ASTMC215-91. The damping

factor of the base was validated using ANSYS 6.0 CAE software. The hybrid base

damping factor was compared with steel and cast iron damping factors. The

hybrid PC machine base exhibited superior damping characteristics (n = 2.93–

5.69%), which enhanced the precision of the CNC milling machine.

In another study with the same focus (Bruni et al., 2008), the effect of a PC base

for a CNC turning machine on dimensional accuracy and tool wear was

57

investigated using 39NiCrMo3 alloy steel in a hard turning operation and the

results were compared with a cast iron base for a CNC turning machine In this

research, two kinds of cutting tools were used. They were ceramic and PCBN,

with lubricant and without. Figure 2.2.7 shows the effect of the machine base

material on tool wear and surface roughness. The general trends obtained under

the same experimental conditions using the cast iron and PC beds are very similar.

However, it can be observed that the machine tool equipped with the PC base, in

respect to the insert material and the lubrication-cooling technique used, obtained

a better surface finish and lower tool flank wear than those given by the cast iron

base.

Figure 2.2.7 (a) Flank wear versus cutting time, (b) surface roughness versus cutting time obtained using polymer concrete and cast iron beds under wet and dry turning conditions (PCBN inserts).

Figure 2.2.8 shows the comparison between the two bases used, in terms of

acceleration time history and the spectrum measured during free vibrations after

an excitation was applied using an impulse hammer. It demonstrates that the PC

58

base is characterized by vibrations with lower amplitude and resonance peaks

than those measured on the cast iron base (Bruni et al., 2008).

Figure 2.2.8 Comparison between cast iron and polymer concrete base in terms of (a) acceleration time history and (b) spectrum measured during free vibrations.

It was concluded from these results that the surface finish and turning performed

on the machine tool equipped with the PC base provided lower flank wear and

higher surface finish values than those given by the same operations carried out

on the turning centre equipped with the cast iron or steel bases (Bruni et al., 2008).

Bai et al. (2009) investigated the influence of glass fibre on the mechanical

properties of PC used as a base for precision tool machines. The most effective

property in PC is the damping ratio. Damping tests were performed for different

PC samples containing different levels of glass fibre, and different amounts of

epoxy resin and granite. Results of the tests showed that the granite volume

fraction had more influence on the damping ratio than the epoxy dosage and glass

59

fibre length, while the amount of resin and the glass fibre dosage had

comparatively less influence (Bai et al., 2009).

Ding (2010) conducted another study on bases for CNC machine tools composed

of epoxy concrete structure faces and steel fibre, with a cement concrete core

(Ding, 2010). This combination of materials satisfied the required properties of

high stiffness and high vibration damping for the machine base, and its low cost

was advantageous. Figure 2.10 illustrates a cross-section of the machine base.

Figure 2.2.9 Cross-section of the CNC machine bed (Ding, 2010).

60

2.8 Conclusion

In conclusion, Flandro established a progressive principal for PC research more

than 50 years ago, which then PC research continued in various directions

depending on the application and research approach. This literature review was

structured to include discussion of the different types of thermosetting resin

binders, the use of thermosetting resins in PC, and the applications of PC in the

manufacture of bases for a precision tool machine. All the directions of PC

research since Flandro were covered in this chapter. Each direction in PC research

focuses on different aspects, depending on the application, the research approach

and previous research. The PC aspects were reviewed in regard to the effect of

polymeric material, such as the damming ratio, mechanical properties and thermal

properties. In respect to the PC as a composite, various aspects were reviewed,

such as fillers, polymeric matrix, curing behaviour, creep behaviour, principal

mechanical properties and thermal properties. Recently, a major focus of PC

research has been the utilization of PET bottle waste as a filler or resin in the

manufacture of PC, being an innovative and environmental approach to the

utilization of the waste with many useful applications. The literature review

identified numerous gaps. Some of those gaps were related to issues in the

manufacturing of PC bases for precision tool machinery, such as:

1. Resin optimization for the mechanical and rheological properties in

accordance with the manufacturing process of PC and the final

structural functionality of precision tool machine bases. This thesis is

filling this gap as described in Chapter 4.

2. Investigation of the allowable moisture content in fillers, based on

the influence of water on the mechanical, thermal and rheological

properties of the polymeric binder and the PC composite system.

61

The investigation filling this gap as described in Chapter 7 and the

amount of allowable moisture nominated.

3. Investigation of the effect of resin and filler volume fractions on the

CTE, damping characteristics and mechanical strength of the PC

composite system. This thesis filling this gap as described in Chapter 5.

4. Investigation into the effect of moulding technology, including the

optimisation of mixing, maximum compaction and vibrating time,

based on the rheological properties of the resin bidder,

morphological properties of the filler and resulting mechanical

properties. This gap is covered in Chapter 6, where the optimum

vibration frequency and time are identified.

5. Identification of the amount of DMA according to the temperature-

time dependant rheological properties of polymeric binder and how

they affect the mechanical properties of the resin and PC composite.

This gap is covered in Chapter 6, which nominates the DMA

amounts according to the temperature and rheological properties of

the matrix.

6. Nomination of the maximum allowable moulding period based on

curing studies and the temperature-time. This gap is covered in

Chapter 6.

7. Identification of a maturing method, compatible with the required

mechanical strength of the base according to the optimization

62

criteria. This gap is investigated in Chapter 8 and the maturing

method is identified based on flexural strength.

8. Identification of the relationship of the PC developed flexural

strength with the maturing time and maturing temperature. This gap

is covered in Chapter 8, and the relationship identified for developed

flexural strength with the maturing time and maturing temperature.

There are other gaps not related to the research area of PC used in the manufacture of bases for precision machines, such as:

1. The effect of the virgin material of MMA monomer on the mechanical properties and curing behaviour of UPE obtained from the depolymerisation of PET bottle waste.

2. The effect of DMA amounts on the curing rate and mechanical properties of UPE obtained by the depolymerisation from HDPE bottles.

3. The relationship between the developed strength on PC contained UPE obtained from PET bottle waste and the temperature with the time.

4. The comparison of UPE virgin material and the UPE obtained from PET bottle waste in terms of thermal properties, such as CTE and thermal conductivity.

5. The effects of gamma radiation on the thermo- mechanical properties of PC containing a UPE as a polymeric binder obtained from PET bottles.

6. The effect of thermal stress and shrinkage induced by the thermal maturing on PC mechanical properties of PC containing UPE obtained from PET bottles.

63

7. The effect of initiators on the rheological and thermo-mechanical properties of UPE obtained from UPE bottles.

8. The suitability of the PC containing UPE as a resin binder obtained from PET bottle waste in the manufacture of a PC base of for a precision tool machine and how it can be accommodated.

9. The use of surfactants as a chemical binder between the aggregates and the matrix to improve the mechanical properties of PC in UPE of a virgin material and the UPE obtained from PET bottles.

64

Chapter 3

3 Materials and Methods

3.1 Polymeric matrix

The resin used in this research is a thermosetting material combining two

commonly used constituents, commercial unsaturated polyester (UPE) and a vinyl

based monomer, methyl methacrylate (MMA). The resin is formed via the radical

copolymerization of the monomer (MMA) and the low molecular weight

unsaturated polyester (UPE) viscose liquid when initiator ( methyl ethel kenton

peroxide (MEKP)), an accelerator (dimethyl aniline (DMA)) and a promoter, cobalt

octoate, are added to bring about the curing reaction. This process produces a

cross-linked three-dimensional network resin. This resin is used as a binder for

aggregates in PC composite systems.

3.1.1 Unsaturated polyester (UP)

UPE resin is available referred to commercially as a combination of unsaturated

polyester with styrene. The resin offers ease of handling, and casting and

moulding operations with little or no pressure (Zaske and Goodman, 1998). The

65

commercial general purpose UPE (AROPOL) is manufactured by the Mitsubishi

Chemical Company in Japan and imported by Hustman Chemical Company

Australia Pty. Ltd. The appearance can be a clear or cloudy, viscous liquid with a

sweet or sharp aromatic odour. Table 3.3.1provides information provided by the

manufacturer. The molecular chemical structure is shown in Figure 3.1:

OO

O

O

n

Figure 3.1 Chemical structure of UPE.

Table 3.3.1 UPE properties supplied by the manufacturer.

Property Description

Vapour pressure Styrene: 4.5 mmHg @ 20 °C

Water solubility Immiscible

Vapour density Styrene: 3.6

Solubility in organic solvent Miscible with acetone, glycol ethers, toluene

Evaporation rate Styrene: 0.5

Percentage of Volatile 30 – 67% by volume

3.1.2 Styrene

Styrene is commonly used as a monomer with UPE. It is a low-cost monomer and

can produce low-viscosity resins that can polymerise with UPE at either room

66

temperature or at a high temperature. The styrene used in this study was

produced by Nupol Composites, a division of Nuplex Industies (Aust) Pty Ltd

NSW, Australia. The specifications, as supplied by the manufacturer, are shown in

Table 3.2. Styrene monomer has a composition of 99-100% of styrene and 10-15

ppm of tertiary butyl catechol (TBS) which is a polymerisation and oxidation

inhibitor.

Table 3.2 Styrene specifications provided by the manufacturer.

Property Description

Vapour density (air=1) 3.6 (air=1)

Evaporation rate 0.49 (n-butyl acetate = 1 )

Odour threshold Approx. 0.1 ppm

Molecular weight (g/mol) 104.14

Specific gravity 0.902 @ 25°C

Auto-ignition (°C) 281

Water solubility Insoluble 0.300 g/L @ 20 °C

Viscosity (mPa.s) 0.763 @ 20 °C

Vapour pressure( kPa) 0.6 kPa @ 20 °C

3.1.3 Methyl methacrylate (MMA)

This organic compound is a monomer with low viscosity. It is colourless and has a

sharp fruity odour. It contains 0.25% inhibitor of hydroquinone to avoid

67

premature polymerisation, and is supplied by Degussa Australia Pty Ltd. Table

3.3 illustrates some of its properties, as provided by the supplier.

Table 3.3 MMA properties provided by the supplier.

Property Description

Density 0.94

Flammability limits (%) 2.1-12.5

Water solubility(g/L) 15.9

Viscosity (mPa.s) 0.63

Vapour pressure( Pa) 38.7

Boiling point (°C) 100.3

3.1.4 Methyl Ethyl Ketone Peroxide (MEKP)

Organic peroxide initiators are the source of free radicals in a variety of plastic

resins and elastomers. They are used in plastic processing for the polymerisation

of thermoset resins such as the curing of unsaturated polyester, cross linking of

polyethylene and various elastomers. There are other kinds of initiators, such as

cyclohexanone peroxide and TMPTMA. The peroxide group (—O—O—) that is

contained in all organic peroxides is highly unstable. When the bond is broken

between two oxygen molecules, the peroxide decomposes and two free radicals

are formed. The general formula for these compounds is R1—O—O—R2, where

R1 and R2 either symbolize organic radicals or an organic radical and hydrogen

atom. MEKP is the main product of the organic ketone peroxides. These types of

68

peroxides are mixtures of peroxides and hydro-peroxides that are commonly used

for room-temperature polyester curing (Kattas et al., 2004). MEKP is a product of

FGI, a division of Nuplex Industries Australia Pty Ltd. Table 3.4 contains

information provided by the MEKP supplier.

Table 3.4 MEKP properties provided by the supplier.

Property Description

Specific gravity 1.15

Auto-ignition (°C) 281

Water Solubility (%) 1

Viscosity (mPa.s) 0.63

Vapour Pressure( kPa) 50 @ 50°C

Appearance Colourless liquid

3.1.5 Promoter

A promoter is a compound that greatly increases the activity of a given initiator.

The promoter helps in the decomposition of the initiator, delivering radicals at low

temperatures. Promoters facilitate curing because the initiator alone does not

decompose at a sufficient rate (Fink, 2005). The promoter used in this study was

cobalt octoate, a product of Alfa Aesar Pty Ltd from USA. Cobalt octoate is a

metallic salt of synthetic carboxylic acid containing 1-12% of cobalt metal and a

mineral spirit as the diluent. Some typical properties of cobalt octoate

specifications, provided by the supplier, are shown in Table 3.5.

69

Table 3.5 Cobalt octoate supplier specifications in different concentrations.

Cobaltoctoate concentration (12%) (10%) (6%) (3%)

Metal content 12 10 6 3

Non-volatile matter 69 60 33 19

Specific gravity @ 30C° 1.02 1.97 0.87 0.83

3.1.6 Accelerator

A chemical compound is used to increase the reaction or curing of thermosetting

materials. Note that the term “accelerator” is often used interchangeably with

“promoter”. An accelerator is often used with a catalyst, hardener or curing agent

(Kattas et al., 2004). The accelerator used in this study was dimethyl aniline

(DMA), a product of Alfa Aesar Pty Ltd, USA. It is a colourless gas with an

ammonia-like smell. Some properties of DMA, as provided by the supplier, are

shown in Table 3.6.

70

Table 3.6 DMA Supplier specifications obtained from the supplier.

Property Descriptions

Molecular weight (g/mol) 100.1

Density (g/cm3) 0.049

Viscosity (mPa*s) o.66

Solubility in water (%) 1.15 @ 20 °C

Boiling point (C°) 100.5

Melting point (C°) -48

Shrinkage on polymerisation (%) 21

Vapour pressure (mbar) 37 @ 20 °C

3.2 Specifications of filler composition of polymer concrete

The aggregates used in PC are basalt, river gravel, spodumene, sand, chalk and fly

ash in different combinations. Basalt, river gravel, sand and chalk were used as

filler aggregates in the precent study.

3.2.1 Basalt

The basalt that used as coarse aggregate in this research was basalt 7 mm from

Roca Pty Ltd. The specifications of the basalt are shown in Table 3.7. The basalt

71

was selected as coarse aggregates since basalt provide a high rigidity and low

CTE. The ecological source of basalt was Walsh Ballarat quarries.

Table 3.7 Specifications of basal obtained from the supplier.

Property Descriptions

Specific gravity 3.00

Chemical stability Stable

Solubility in water Immiscible

Odour Odourless

3.2.2 Gravel

The gravel used as course aggregate in preparing PC samples was 7 mm gravel

from Roca Pty Ltd. The specifications of the gravel are shown in Table 3.8. The

gravel was selected for a comparison resin with the basalt. The ecological source of

gravel was Kingston quarries in Melbourne.

72

Table 3.8 Specifications of gravel delivered by the supplier.

Property Descriptions

Specific gravity 2.80

Chemical stability Stable

Solubility in water immiscible

Odour Odourless

3.2.3 Sand

The sand used in the present study in the preparation of the PC samples was a

middle-sized aggregate supplied by Roca Pty Ltd. The basalt was selected because

of it is availability and high compaction. The ecological source of sand was

Essendon quarries in Melbourne. The specifications of the sand are shown in the

following table:

Table 3.9 Sand specifications obtained from the supplier.

Properties Descriptions

Specific gravity 2.6

Chemical stability Stable

Solubility in water Immiscible

Odour Odourless

73

3.2.4 Spodumene

Spodumene is a lithium aluminium silicate. It is a non-toxic and inert substance,

unlike lithium, which is a reactive substance. Spodumene is a source of lithium for

applications such as batteries. The spodumene was selected because of it is very

low CTE and high texture. The spodumene was supplied by Talison Minerals,

Western Australia Pty Ltd. The chemical contents of spodumene provided by the

supplier are shown in Table 3.10.

Table 3.10 chemical contents of spodumene obtained from the supplier.

Chemical content Volume fraction (%)

Li2 O 5.0 Fe2 O3 0.1 Al2 O3 18.5 SiO2 75.0 Na2 O 0.25 K2 O 0.35

3.2.5 Fly ash

Fly ash is a fine grey powder consisting mainly of spherical glassy particles that

are produced as a by-product in coal fired power stations. The fly ash was

74

supplied by Cement Australia Pty Ltd. The geological source is Bayswater power

plant. The fly ash specifications are shown in Table 3.11.

Table 3.11 Fly ash specifications obtained from the supplier.

3.2.6 Chalk

Chalk is a porous powder from limestone composed of mineral calcite (CaCo3).

The chalk used in the study was supplied by Omya Australia Pty Ltd. The

specifications of the chalk are shown in Table 3.12

Property Descriptions

Specific gravity 1.4

Melting point (°C) 1400

PH Basic (11.9)

Solubility in water 1.3 mg/100g

Odour Odourless

75

Table 3.12 Chalk specifications obtained from the supplier.

3.3 Methods of measuring properties of fillers

Different properties were measured for each aggregate, including particle size

distribution, bulk density, true density, Brunauer, Emmett, and Teller (BET)

surface area and morphological properties using scanning electron microscopy

(SEM). The methods of testing are explained in the following sections:

3.3.1 Sieve analysis

Particle size distributions were obtained for course and middle-sized aggregates

such as basalt, river gravel, sand and spodumene using sieve analysis with

different sieve sizes, depending on aggregate particle size distributions. The

procedure starts with a nest of sieves that is prepared by stacking the test sieves

one on top of another. The largest opening is at the top, followed by sieves with

progressively smaller openings and a catch pan at the bottom. A sample of 400g

Property Descriptions

Specific gravity 2.7 Melting point 825 °C Chemical formula CaCo3 Solubility in water

Odour

1.3 mg/100g

Odourless

76

dry aggregate is poured onto the top sieve to cover the nest which is then shaken

mechanically for 10 minutes until each particle has dropped to a sieve with

openings too small to pass, thus retaining the particle. The accumulative weight of

all material larger than each sieve size is determined and divided by the total

sample weight to obtain the percentage retained for that sieve size. This value is

subtracted from 100% to obtain the percentage passing that sieve size. The results

are displayed after plotting the percentage passing through the sieve opening size

and connecting the plotted points with a smooth curve.

3.3.2 Determination of the particle size distribution using laser scattering

The particle size distributions of micro-size fillers such as chalk and fly ash were

obtained using a Malvern Mastersizer X, manufactured by Malvern Instruments

Ltd. UK. This equipment was implemented because the filler particle size cannot

be detected using conventional sieves, and accurate results were needed to

enhance the research outcomes. This method operates on the observation of

patterns of light scattered at various angles, which is one way of measuring

particle size distributions (Frock, 1987). The low angle scattering method can be

applied to particles with large dimensions compared to the wavelength producing

the scatter. The method relies on the fact that the diffraction angle is inversely

proportional to the particle size. The optical configuration is shown schematically

in Figure 3.2. The instrument is equipped with a low power helium-neon laser that

measures particles with a maximum size of 600 µm with an accuracy of 2 % on

volume median diameter. The results of particle size distribution measurements at

a wavelength of 0.63 µm, are used to form a collimated beam of light. Particles are

introduced to this beam by the sample presentation modules and scatter the laser

77

light. The light scattered by the particles and the unchartered remainder is

analysed by the special semiconductor detector in the form of a series of concentric

annular sectors. Figure 3.2 shows a schematic diagram of the laser scattering

process. The results are converted into an electronic signal sent to the computer for

analysis by special software provided with the instruments. Figure 3.3 shows the

computer results that can be converted into an Excel file using interface software.

Figure 3.2 Schematic configuration is of Malvern Mastersizer X.

78

Figure 3.3 The results of particle size distribution of fly ash obtained from the Malvern Mastersizer software that can be converted into Excel.

3.3.3 Bulk density

Bulk density was measured using a measuring cylinder in a simple procedure. The

sample was weighed then poured into a measuring cylinder then compacted into

the measuring cylinder. The volume of the sample was obtained using the

measuring cylinder and the mass of the sample was known. The density was

calculated by dividing the mass over the volume.

79

3.3.4 True density

The density of the aggregates was measured using a pycnometer (density bottle).

The dry bottle, aggregate sample and bottle with sample and acetone were

weighed and the sample weight, volume and density were calculated accordingly.

3.3.5 BET (Brunauer, Emmett, and Teller) surface area

The BET specific surface areas and porosity were determined using nitrogen

sorption measurements that were performed using a Micromeritics ASAP 2000

(USA). Surface area and porosimetry were determined by nitrogen gas

adsorption/desorption. In a typical test, a 100-150 mg sample was degassed at

fixed temperatures under high vacuum for at least 22 h, prior to measuring the

isotherms at liquid nitrogen temperature (77°K). The same samples were degassed

at gradually increasing temperatures up to 250°C and the N2 adsorption isotherms

were measured after each step of degassing using an 89-point pressure table with

15 s equilibration intervals. The surface areas were determined using the BET

method, and the average pore diameter and pore size distribution were evaluated

using the Barret, Joyner and Halenda (BJH) theory applied to the desorption

branch.

3.3.6 Method of measuring aggregate moisture content

The moisture content of the aggregates has a great effect on the mechanical The

moisture content of the aggregate has a great effect on the mechanical properties

and curing behaviour of a PC composite system. Prior to mixing the aggregates

with resin, a moisture test should be performed to obtain an indication of the

moisture levels in the system. The level of moisture in the aggregates is preferably

80

at zero or as close as possible. The device used for measuring the moisture content

of aggregate was an MD 150 from Sartorius, Germany. This is a specialized

measuring instrument for this application. The MD 150’s working principle is that

thermo-gravity determines the loss of mass that occurs when substances are

heated. In this process, the sample is weighed before and after being heated and

the difference between the two weights is determined, which is the moisture

content. The heating element in the MD 150 is infrared radiation, which has high

heat penetration. The procedure takes up to 30 – 40 minutes, with a gentle heating

temperature of 150 ˚C.

3.4 Methods of testing polymeric matrix

The polymeric matrix was tested for different properties, such as flexural strength,

tensile strength, modulus of elasticity, elongation, hardness, the damping factor

and the CTE. Furthermore, the resin was subjected to numerous analyses to

capture a potential explanation for the resin behaviour or parametric effect.

Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry

(DSC), rheology analysis and scanning electron microscopy (SEM) were used.

3.4.1 Methods of testing mechanical and thermal properties for polymeric

matrix

Different mechanical properties of the polymeric matrix were tested, including

tensile strength, flexural strength, shore D hardness, damping factor and CTE. In

the next sections, each method of testing mechanical properties is described in

detail.

81

3.4.1.1 Methods of testing tensile and flexural strength

Flexural strength and tensile strength were tested using a Zwick universal testing

machine (Zwick Z010, Germany), as shown in Figure 3.4. Resin samples were

prepared using a high density polyethylene (HDPE) mould with the following

dimensions: 50 mm long × 10 mm wide × 2.5 mm thick.

Figure 3.4 Zwick universal testing machine.

For tensile testing, a sample is inserted in both jaws of the universal testing

machine at the centre of the jaws in a vertical orientation. The cross sectional

dimensions of the sample are measured using a dial calliper and the dimensions

are then entered into the testXpertII software available on the computer connected

to the universal machine. The cross-head speed is 25 mm/min, since once the set-

up is accomplished, initiating the test can be either by the mechanical start button

82

on the machine or by the computer software. Once the specimen has failed, the

stress-elongation curve can be obtained and the modulus of elasticity for tensile

stress derived using testXpertII software. Flexural strength testing was conducted

using the same machine by applying a different setting. It was necessary to input

the width and thickness of the rectangular sample into the test XpertII software

and the span of a simply supported cantilever to obtain the flexural strength and

the deflection, as well as the modulus of elasticity for flexural strength.

3.4.1.2 Hardness (Shore D Test Method)

Hardness was tested using a digital Shore D tester 3130/3131 made by Zwick and

a check device Zwick 7507. Both combinations were used to measure hardness

when using the Shore D Test Method.

The sample was moulded in an HDPE cylindrical mould and machined lightly to

the following dimensions: 10 mm diameter and 70 mm length. The time was set

for three seconds for measurement by the digital shore tester, and the sample was

then placed under the loading hull. The loading hull was pressed until the desired

contact pressure was applied, using the actuating lever, the measured value was

displayed in the Digital Shore D Tester. Four measurements per sample were

performed at four random points.

3.4.1.3 Coefficient of thermal expansion (CTE) for the resin

The CTE was measured using a custom-built device. The device includes a heating

chamber (Thumler model TH2700-26, Germany) with two displacement probes

attached to a small digital display unit (Sylvac Dsos, Switzerland) and a

thermostat connected to a temperature control microprocessor. The resin sample

83

temperature was monitored using a data acquisition system linked to a computer,

as illustrated in Figure 3.5.

Figure 3.5 Measuring device coefficient of thermal expansion (CTE).

Two rods made of Invar (a 36% nickel-iron alloy with the lowest CTE of metals

and alloys in the 20 - 230 °C range, iα = 1.2×10-6 °C-1) are used in this set-up. One

of the rods is used as a reference and the other one is placed above the PC sample.

The expansion of the reference rod and the sample with the second rod is detected

by the probes on the top of the heating chamber, which are touching the Invar

rods. Figure 3.6 shows the arrangement inside the heating chamber.

84

Figure 3.6 Arrangement inside the heating chamber with other components of the experimental set-up.

The resin sample has a hole at the side wall of the cylinder sample in order to

place the thermocouple sensor (SE00 type K thermocouple, Pico Technology, UK),

and to monitor and control the temperature inside the sample. The Pico data

acquisition system contains a TC-08 thermocouple data logger (Pico Technology,

UK) connected to the computer to display the temperature. Due to the low thermal

conductivity of PC resin, approximately one hour is required to achieve thermal

equilibrium. Thermal expansions at five temperatures: 25, 35, 40, 50 and 60 °C

were measured to calculate the CTE of each UPE resin sample using Equation 3.4,

which is derived based on the physical principles of CTE as follows:

85

)4.3........(....................

)3.3.........(....................)2.3........(..........

)1.3.......(..........

is

s

s

sis

siss

sirissri

siri

ssri

Tls

TlTlS

TlTlSTlTlTlTlS

RLSTlTlRTlTlL

αα

αα

αααααα

αααα

+∆∆

=

∆∆+∆

=

∆−∆=∆∆−∆−∆+∆=∆

∆−∆=∆∆+∆=∆∆+∆=∆

where ΔL is the change in length of the Invar rod and the sample within the

temperature difference ΔT, and ΔR is the change in length of the reference Invar

rod within the same temperature difference ΔT. ΔS is the difference between the

readings of the two probes i.e. the difference between ΔL and ΔR. rl is the length

of the invar rod, which is located in the middle of the resin sample and sl is the

length of the resin sample. il is the length of the reference rod. Substituting

equations 3.1 and 3.2 in to equation 3.3 and using simple algebra simplifications,

results in equation 3.4 can be used to calculate the CTE polymer concrete and sα is

the sample coefficient of thermal expansion.

3.4.1.4 DMA analysis

To calculate the resin damping factor, Dynamic Mechanical Analyses (DMA) were

conducted, since the damping factor is a dynamic property. DMA is a method

where a small deformation is applied to a sample in a cyclic force that leads the

materials response to stress, temperature, frequency and other parameters. DMA

86

applies an oscillatory force at a set frequency to the sample and reports changes in

stiffness and damping. DMA data are used to obtain modulus information. A TA

Instruments, DMA 2980 USA, was employed to perform a frequency sweep for the

dual cantilever test for measuring tan δ (damping factor), storage modulus and

loss modulus. The sample size of the resin was the same as that prepared for the

mechanical test. A sample is mounted on the clamps and tightened up with

screws, using a torque meter to measure the torque while tightening. Each

material is tightened to a specific torque according to the instructions provided by

TA Instruments. The required torque for PCR was 8 kN/mm. The furnace should

be closed and the type of analysis is specified (a frequency sweep, temperature

sweep or other available analysis), using the TA Instruments thermal advantage

software that controls the device through a computer. Figure 3.7 illustrates the

thermal advantage software interface. Analyses that were conducted mainly used

the isothermal frequency sweep. Other information which must entered is the

deflection, the time for isothermal equilibrium, testing temperature, sample

geometry, dimensions, clamp type and sample name.

Figure 3.7 Thermal Advantage software.

87

The analysis can be run when all the required data are entered. On accomplishing

the analysis, the results can be obtained using TA universal software 2000. Figure

3.8 shows the result of a temperature sweep (50-200°C) for a given range of

frequencies (1-200 Hz) for UPE resin containing 0.005 DMA accelerator. The

analysis illustrates changes in the material damping factor (tan δ) and storage

modulus with temperature and time.

Figure 3.8 TA Universal 200 viewing DAM analysis file.

3.4.2 Rheological analysis

Rheological analysis was conducted in order to understand and analyse the curing

behaviour of the polymeric matrix. There are two types, one measuring the

viscosity growth due to the cross-linking process through the polymerization, and

the other measuring the temperature profile for the resin due to the exothermal

reaction that generates heat (exothermal energy). The experimental procedure for

88

both will be described. Another measure of viscosity growth is the gel time, which

is another indication of curing.

3.4.2.1 Measurement of viscosity growth during polymerisation

The Brookfield UL (universal left) adapter set was used, which included: a

locating channel assembly, chamber tube, collar with thumbwheel, tube end cap

and spindle LV-1 with universal coupling. The assembly of a rheological system:

All parts of the system are manufactured by Brookfield, USA. The viscosity

growth through the polymerisation was measured using the following equipment:

§ Brookfield RVDV-II+ Pro programmable viscometer.

§ Brookfield UL adapter.

§ Brookfield circulating bath with digital controller TC-102.

Viscosity measurement was taken at 25°C for all sample compositions. The

Brookfield circulating bath with a digital controller was set at 25°C and the

Brookfield UL adapter immersed for a period of 10 minutes to assure thermal

equilibrium throughout the chamber tube. In sequence, the Brookfield RVDV-II+

Pro programmable Viscometer was set up to run at a speed of 100 rpm and the

entry code for the LV-1 spindle was selected prior to any reading. The Brookfield

RVDV-II+ Pro Programmable viscometer ran in stand-alone mode. The locating

channel assembly was fixed to the Brookfield viscometer, which was used to

assemble the UL adapter with the sample. In order to begin the viscosity

measurements, the resin components were mixed according to the composition

set. The resin was poured into the chamber tube, followed by insertion of the

spindle LV-1 in the chamber and the final assembly of the chamber with the

sample, which was connected to the locating channel assembly to run

89

measurements. The time was recorded with each reading of the viscosity. The flow

chart of a viscosity measurement is shown in Figure 3.9.

Figure 3.9 Flowchart of the procedure for measuring resin viscosity.

3.4.2.2 Method of monitoring resin temperature profile during

polymerisation.

The procedure begins by setting the temperature of the Brookfield circulating bath

using a digital controller TC-102 for 25°C with a wait time of 10 minutes to obtain

thermal equilibrium. The resin is prepared and poured into the high density

polyethylene (HDPE) tube, then immersed in the bath and held by a holder, as

shown in Figure 3.10. A thermocouple sensor (SE00 type K thermocouple, Pico

Technology, UK) is placed in the resin and connected to the Pico data acquisition

system containing a TC-08 thermocouple data logger (Pico Technology, UK) and

connected to a computer to display to record the temperature profile during the

copolymerisation of UPE resin during the copolymerization. Figure 3.10 shows the

90

experimental arrangement. The resin temperature profile was measured during

the polymerization using the following equipment:

• Brookfield circulating bath with digital controller TC-102.

• Tube holder, tube 50 ml.

• Thermocouple sensor (SE00 type K thermocouple, Pico Technology, UK).

• Pico data acquisition system contain TC-08 thermocouple data logger (Pico

Technology, UK)(identical to that used in measuring temperature for CTE).

• Computer for data collection system.

Figure 3.10 Experimental arrangements for measuring temperature during the curing of the resin.

91

A computer records the temperature and the time using Pico technology software

in a pad file that can be converted to an Excel file to plot the temperature versus

time.

3.4.2.3 Method of measuring gel time

Gel time is the period of time when the resin changes from a liquid to a non-

flowing gel. Gel time was determined for the resin according to ASTM D 2471-99

(American Society for Testing and Materials, 2007). A white wooden stick 1 cm in

diameter is inserted, then lifted up through a 20 mL resin sample to detect the

adherence of the resin to the wooden stick. At the same time, a thermocouple is

inserted into the geometric centre of the reacting mixture using the thermocouple

data logger PICO system, previously described for the CTE measuring method. At

the resin reacting gel stage, when the material no longer adheres to the end of a

clean wooden stick, the gel time is recorded.

3.4.3 Thermal analysis

Thermal analysis was conducted in order to understand and analyse various

aspects of polymeric binder such as conversion rate and mass change rate when

the sample under the effect of heat. Those analysis such as:

§ Differential scanning calorimetry (DSC)

§ Thermogravimetric analysis (TGA)

3.4.3.1 Differential Scanning Calorimetry (DSC)

DSC is part of a group of techniques called Thermal analysis (TA), which is based

upon the detection of changes in the heat content (enthalpy) or the specific heat of

92

a sample. As thermal energy is supplied to the sample, enthalpy increases and the

temperature rises by a determined amount, for a given energy input, by the

specific heat of the sample. The specific heat of a material changes slowly with

temperature in a particular physical state, but alters discontinuously at a change of

state. By increasing the sample temperature, the supply of thermal energy may

induce physical or chemical processes in the sample, for example melting or

decomposition, accompanied by a change in enthalpy. Such changes in enthalpy

may be detected by thermal analysis and related to the processes occurring in the

sample. The material, equipment and software used in the DSC measurements

were:

• DSC 2920 Modulated DSC (Figure 3.11-b).

• Thermal Advantage (Version 1.3.0.205), by TA Instruments.

• Precisa 125A Balance (Figure 3.11-a).

• TA Instruments hermetic aluminium pans (Figure 3.11-a).

• TA Instruments T zero press (Figure 3.11-a).

• Eppendorf pipettes.

DSC preparation starts with the weighing of the hermetic aluminium pan, using

the Precisa 125A balance. The resin constituents are then prepared and mixed

constantly and slowly for a few seconds with a mixing paddle. To avoid heat

transfer, the mixing container case is not hand-held. Instead, the mixing container

is placed on an insulated non-conductive surface. The mixture is stirred at room

temperature and a sample of 5-20mg is taken using an Eppendorf pipette and then

sealed hermetically into a hermetic aluminium pan. The hermetically-sealed

sample can either be stored at minus 20ºC in order to avoid a reaction or put in the

DSC furnace immediately after mixing and sealing, ready for DSC measurement.

To begin DSC measurement, a sample pan and another empty pan (also

93

hermetically sealed and used as a reference) are placed into the DCS. Prior to this,

the furnace is set up using DSC software (Thermal Advantage software version

1.3.0.205). The DSC furnace is first equilibrated at the isothermal selected

temperature, when the sample hermetic pan and the reference pan are placed in

the DCS furnace, Figure 3.11(c) and Figure 3.11(d) show the furnace details.

Isothermal experiments were established to run at 80 ºC for 180 minutes. Figure

3.12 illustrates the DSC procedure using a flowchart.

(a) (b)

(c) (d)

Figure 3.11 DSC Analysis: (a) Precisa 125A Balance; TA Instruments Tzero press; and TA Instruments hermetic aluminium pans. (b) Modulated DSC 2920. (c) Modulated DSC 2920 Furnace. (d) Upper view of modulated DSC 2920 Furnace.

94

Figure 3.12 DSC procedures.

3.4.3.2 Thermal Gravimetry Analysis (TGA)

TGA tests weight changes in a material as a function of temperature or time under

a controlled environment. Its fundamental uses include measurement of a

material's thermal stability and composition. TGA tests were conducted using a

Perkin Elmer (USA) TGA7 analyser attached to a TAC controller, gas changer and

computer. The samples (2-5 mg) were heated to 700°C at a heating rate of

10°C/min under nitrogen (20 mL/min). A platinum crucible was used as the

reference. Ample was scanned at 10 °C/min from 30 °C (close to ambient). At 700

°C automatic gas was switched to air (oxygen present to oxidize and residue to

carbon dioxide). At 750 °C the scan stopped, as any residue after air oxidation will

not be organic.

95

3.4.4 Scanning Electron Microscopy (SEM)

The morphology of the samples was studied using SEM. PC resin or PC

composite was affixed to aluminium pegs with carbon tape, then sputter- coated

with gold for 60 seconds at 0.016 mA (Ar plasma) using an SPI-Module sputter

coater (SPI Supplies Division of Structure Probe, Inc.). SEM images were then

obtained using a German Zeiss Supra 40 VP electron microscope operating with a

high vacuum, as shown in Figure 3.13.

Figure 3.13 ZEISS Supra 40 VP SEM.

3.4.5 Fourier Transform Infrared Spectroscopy (ATR-FTIR)

ATR-FTIR measurements in attenuated total reflectance mode (Spectrum 100,

PerkinElmer) were carried out with a universal diamond ATR top plate accessory

in the scanning range 4000 to 550 cm-1 with a resolution of 2 cm-1 and with 8 scans

for each spectrum.

96

3.5 Methods of testing polymer concrete composite system

The mechanical properties of PC composite systems were studied and the results

are presented in following sections. The method of sample preparation is

described prior to all testing methods. Mechanical properties such as compression

strength and flexural strength were tested according to Australian standards. CTE

were measured using the same techniques as were used for the resin. The

structural damping factor was measured for a system containing a PC sample

damping factor. This procedure is not a method for measuring the damping factor

of PC as a material property it provides an indication of the damping factor for the

PC. All the properties that measured is in accordance with the selection criteria of

the PC base manufactured for the precision tool machine.

3.5.1 Sample preparation for polymer concrete composite system

Aggregate preparation begins with the preparation of the appropriate amount of

each aggregate. In these samples, 60% basalt, 30% sand and 10% of fly ash was

used. The overall aggregate volume fraction was 83% and the remainder was

resin. Figure 3.14 illustrates all aggregates used in the PC mixes for different

compositions.

97

Figure 3.14 Aggregates used in polymer concrete for different compositions.

All the aggregates were kept for three hours inside the vacuum chamber to reduce

the moisture content to approximately zero. During this process, the temperature

in the vacuum chamber reached 160 °C. When the aggregates cooled down, the

moisture content was checked according to the method described in Section 3.3.6.

Figure 3.15 shows the vacuum chamber during the drying process of the

aggregates.

Figure 3.15 Drying aggregates using vacuum chamber.

98

Resin preparation was carried out by mixing the following chemical composition,

as shown in Table 3.13, where the resin volume fraction was 17%. Resin volume

fraction and aggregate volume fractions varied, depending on the intention of

each experiment.

Table 3.13 Resin chemical constituencies and volume fraction for each.

Chemical constituents Volume fraction

MMA, (%) 60 ARAPOLE, (%) 40 Cobalt peroxide,(%) 0.8 MEKPT, (%) 2 DMA, (%) 0.2

Once the resin compounds were mixed with the initiator (MEKP), the PC

composite mixing process started by mixing the smallest size aggregates (fly ash

or chalk) with the whole amount of resin using a traditional concrete mixer. Once

the fly ash had been mixed with the resin until all the fly ash was wetted by the

resin, the next size aggregate (sand or spodumene) was added. Mixing continued

until the sand and the fly ash were completely wetted. The coarse aggregate was

added last. Upon completion, the PC mixture was poured into the mould and,

during pouring, the mixture was compacted using a wooden stick. When the

pouring of the polymer concrete was finished, the mould was transferred to a

vibrating table. G-clamps were used to fix the mould onto the vibrating table for

further compaction and particle settling. The frequency was set to 22Hz. The time

required for the particles to settle was determined by observation of the resin

99

bubbling in the PC composite during the vibration process. The resin started

floating after 7 -10 minutes or less and the resin bubbling usually appeared to stop

after 12-15 minutes. Figure 3.16 shows the mould mounted on the vibrating table.

The mixing process for preparing the PC sample was standard sequence of adding

the materials. Mixer was a regular concrete mixer, the speed of mixing was 100

RPM and the mix seemed to be non- uniform.

.

(a) (b)

Figure 3.16 Mould mounted on the vibrating table using G-clamps for sample preparation, (a) compression test mould and (b) flexural tests mould.

Once settled, the sample was transferred to the ventilated curing room to avoid

the smell coming from PC as it is an occupational hazard under Health and Safety

regulations. The PC samples stayed in the curing room for up to 28 days before

being transferred to the testing facility for compressive or flexural tests.

100

3.5.2 Compressive strength

Compressive tests were carried out according to Australian standards AS 1012-

8.2.2000. Cylindrical specimen size was a diameter of 100 mm in diameter × 210

mm high, as shown Figure 3.17.

Figure 3.17 Sample for a compressive test (AS 1012.9-1986).

The mould used for making the sample was steel, covered by a releasing agent

and gel-coated, as illustrated in Figure 3.18. The purpose of the gel coat was to

facilitate the release of the sample.

101

Figure 3.18 Gel coated cylindrical steel mould.

The testing machine used was a German-built Alpha 3, with two columns, with a

crosshead speed of 0.5 mm/min. A ring frame holding three distance sensors was

mounted on the sample for lateral displacement, while the machine itself

measured the longitudinal displacement. The outcome could be plotted in a stress-

strain diagram. Figure 3.19 shows the experimental set up.

Figure 3.19 Compression test for polymer concrete sample.

102

3.5.3 Flexural strength

The flexural strength was determined in accordance with Australian standards AS

1012.11-2000 Figure 3.20 and Table 3.14 demonstrate the standard’s test setting for

flexural strength. The testing machine is a German built Snitch 60/D, with a

universal testing machine load range of 300KN. The crosshead speed during the

test was 0.5mm/min, and the calibration remained valid at the time of testing.

Figure 3.20 Test settings for flexural strength according to AS 1012.11-2000.

Table 3.14 Centre-to-centre distance of the supporting and loading roller for

100X100 cross-section samples prepared for flexural strength test.

Supporting roles L,(mm) 300 +8,-3

Loading roles l ,(mm) l = L/3

103

The mould was designed using Pro/Engineer software according to the

Australian standards, as shown in Figure 3.21 and Figure 3.22. The mould was

fully disassembled to overcome all the difficulties that might occur when the

sample was fully cured and ready for removal from the mould but a coat of gel

was still needed to ease the release of the PC sample from the mould. Figure 3.23

shows the Snitech 60/D during a flexural test.

Figure 3.21 Fully disassembled rectangular mould for preparing a flexural strength sample.

104

Figure 3.22 Fully disassembled rectangle mould manufactured and ready to be used.

Figure 3.23 Sintech 60/D universal testing machine for conducting a flexural test according to AS 1012.11-2000.

105

The fracture within the middle third of a specimen’s flexural strength can be

calculated as follows:

)1.3.........(...................................................

)1000(2DB

plfcf =

where:

cff = Modulus of rupture, in mega Pascals.

p = Maximum applied force indicated by the testing machine, in kilo newtons

(kN).

l = Span length, in millimetres.

B=Average width of the specimen at the section of failure, in millimetres.

D= Average depth of specimen at the section of failure, in millimetres.

3.5.4 Measuring the structural damping ratio for a system containing 85-90%

polymer concrete

This test does not identify the damping ratio of PC as a material property. The test

is to identify the damping ratio of a structural system that consists of 85-90% PC.

Furthermore, it reveals the damping ratio of PC that could affect the overall

structural system-damping ratio. It also reveals the effect of the main source of

damping, namely the resin, and how the resin volume fraction affects the overall

structural damping ratio. A tap test was used to measure the damping ratio. In

this test, a PC sample is set as a simple supported beam and tapped by hand. The

frequency response is detected, and then the damping ratio is calculated using one

of the methods available to calculate the damping ratio. Prior to describing the

method in detail, the details of the samples and the mould will be described. The

mould was designed using Pro/Engineer software. Figure 3.24 illustrates a

detailed drawing of the mould assembly.

106

Figure 3.24 Cross-section and exploded assembly drawing for the mould used for preparing a PC sample for the purpose of measuring damping ratio.

The following considerations were followed when designing the mould:

It must be thinner and longer than the flexural strength mould. It must be fully

disassembled to consider the adhesion of the PC. In addition, ease of assembly and

disassembly as well as safety must be carefully accommodated in the design. The

dimensions of the samples produced by the mould were 500 mm ×50 mm ×25

mm.

The structural design of the sample is set up as a simply supported beam as it is

quite similar to the structural design of the bases for precision tool machines.

Figure 3.25 illustrates the PC sample and an accelerometer mounted to capture the

frequency and the amplitude in Z direction. An accelerometer model 3192A, was

connected to the amplifier model MODE4114B1. Both were made by Dytran

Instruments, USA.

107

Figure 3.25 The accelerometer mounted on PC sample.

The amplifier was connected to the data acquisition system Model SCI-1000, made

in Hungary by National Instruments, which fed the data to the computer to be

analysed using data interface software (Lab view). Figure 3.26 shows the

amplifier, data acquisition system and the computer. The measurement of the

frequency and the amplitudes starts when the sample is tapped and the

accelerometer captures the movements of the sample. The accelerometer converts

the sample movements to a voltage signal that is amplified for transfer to the data

acquisition system. It is then converted into a digital signal using a DAQ data card

made by National Instruments, USA. The computer receives a digital signal to be

analysed by software signal analysis, which presents the data in the time domain

or frequency domain, as required.

108

3.26 The amplifier connected to both the accelerometer and data acquisition system to supply data to the computer.

There are different methods of estimating the damping ratio, using either time or

frequency domain analysis. Logarithmic Decrement Analysis (LDA) can be used

for the time domain analysis and Half Power Bandwidth (HPB) can be used for

the frequency domain analysis. For this study, LDA was chosen to calculate the

structural damping ratio. Figure 3.27 illustrates the LDA analysis. The decay in

vibration amplitude, which is defined as the natural log of the ratio of the size of

two peaks, m cycles apart, can be estimated using Equation 3.2.

)2.3(..........ln1mn

n

yy

m +

=δ

109

where yn is the amplitude of the nth cycle and yn+m is the amplitude of the n+mth

cycle. The damping ration can then be found from Equation 3.3.

)3.3..(..........2πδζ =

Figure 3.27 Logarithmic Decrement Analyses (LDA).

The time domain can be obtained with a tap test obtained using Excel, as shown in

Figure 3.28. The structural damping ratio can be calculated using the LDA

method.

110

-10

-5

0

5

10

15

1 1.5 2 2.5 3 3.5 4

Time (S)

Ampt

itude

(µm

)

Figure 3.28 Time domain obtained using Lab View software.

3.5.5 Measuring coefficient of thermal expansion (CTE) for PC composite

The only difference in measuring CTE for PC as a composite material is

the sample size. The samples used for flexural strength testing were

identical to those used for the CTE test, with the same equipment and

formulas. Figure 3.29 illustrates the custom-built device in a schematic

diagram with the set-up for measuring the CTE of PC composite.

111

Figure 3.29 Schematic diagram of CTE custom-built device.

112

Chapter 4

4 Optimization of polymeric matrix

4.1 Introduction

This chapter describes the effect of resin’s chemical composition on the CTE,

damping factor, flexural strength, tensile strength and hardness through

procedures to determine the optimum resin for use as a resin binder in PC for the

bases of precision tool machines. The nature of the application requires a PC with

high damping, low CTE and high flexural strength. The main source of the

properties required by the application is the resin. Resins of various ratios of

styrene: ARAPOL and methyl methacrylate (MMA): ARAPOL (36% UPE and 33%

styrene) were made and the curing kinetics were followed using viscosity

measurements and exothermic reaction temperature profiles. The resins were

studied using dynamic mechanical analysis and in-house thermal expansion

measuring devices. In addition, resin kinetic analysis was considered in resin-

aggregate mixing performance to achieve the lowest viscosity for the optimized

resin. The exothermic reaction temperature profile was also considered, to

113

determine the lowest level to avoid thermal degradation and thermal stresses in

order to eliminate a potential fatigue point. This ensured that the nominated resin

was equipped with superior mechanical strength and the optimum capacity to

damp the unwanted vibration generated during operation of the precision tool

machine, and to have a low CTE.

4.2 Curing of unsaturated polyester resin

The curing of UPE resin is a radical polymerization process involving three steps:

initiation, a propagation process, and a termination step. The initiator used was

MEKP, which produces a radical species at room temperature. The unsaturated

polyester used was ARAPOL. This is an industrial mixture of UP (67%) and

styrene (33%). Another vinyl-based monomer (MMA) was added to this mixture

to reduce the viscosity and improve the mixing and potential mechanical

properties. Cobalt octoate was used as a promoter in the curing process. During

resin curing, the material went through three phases: viscous liquid, gel and solid.

Each phase was imprinted by incentive conversions in the thermo-mechanical

properties of the resin (Ramana Reddy et al., 2002)

UP + MMA + St + MEKPTDMA

Co OctoateCrosslinked Resin

114

4.2.1 Initiation step:

The initiation step starts with the production of free radical species from the

initiator, followed by the first monomer, which may be the unsaturated bonds in

the UPE, styrene or MMA monomers, based on their reactivity ratio Figure 4.1

shows the initiation step.

O

O

OO

OOH

OOH

MEKPT

MMA

Light or heatOHO

OOH

OO

OOH

O

R O C O

O

OR+

+ +

Styrene

R O+CH O

R

Figure 4.1 Initiation step for polymerization

4.2.2 Propagation step:

The propagation step proceeds when the radical species produced in the initiation

step reacts with double bonds in the unsaturated segments (Sidney, 1986) of the

UPE (UP) or, MMA or styrene, as shown in Figure 4.2.

115

C O

O

OR

O O

OO

O

O

O

O

OO

UPS

O O

OO

O CH

O

O

O

R

O

O

OR

+nm

k

Figure 4.2 Propagation step for unsaturated polyester resin

The presence of multiple unsaturated bonds in the UPE causes the growth of the

resin in a cross-linked network form during this step.

4.2.3 Termination step:

The termination step ends the growth of the living radical ends in the growing

segments of the polymeric network. This can occur through the reaction of two

radical ends or the free radical species with growing ends. It produces a saturated

bond, as shown in Figure 4.3.

116

OH O

OOH

OO

OOH

O

R OC O

O

OR

+

CH OR

CH

O O

OO

O

O

O

O

R

O

O

OR

O O

OO

O

O

O

O

R

O

O

OR

R

Figure 4.3 Termination step of unsaturated polyester copolymerization

The UPE resin curing process is an exothermic reaction. Thus the rate of this

process is essential to the dissipation of the produced heat, and the integrity and

uniformity of the resin produced. Here MMA monomers was used to reduce the

reaction rate based on MMA reactivity ratio (Gan et al., 1994).

117

4.3 Rheological analysis

The purpose of the rheological analysis was to nominate the resin composition

according to the optimization criteria for the resin binder in the PC used in bases

for precision machinery. Rheological analysis was conducted to examine the effect

of the addition of different proportions of styrene and MMA on the viscosity

growth and exothermic temperature of the resin binder. According to the

optimization criteria, the nominated resin should have the lowest viscosity growth

and exothermic temperature.

4.3.1 The effect of styrene/UPE ratio

The effect of the styrene/UPE ratio on the curing rate was investigated by

increasing the initial 30:70 ratio in ARAPOL and adding more styrene to the

mixture. The addition of excess styrene reduced the initial viscosity of the mixture

and increased the gel time in the curing process. The ARAPOL/styrene ratio was

varied from 68:32 (68% ARAPOL) to 25:75 (25% ARAPOL) causing the viscosity

growth rate to increase, as shown in Figure 4.4. The gel time increased from 1

minute to 28 minutes, as illustrated in Figure 4.6 based on gel time measurement.

The method is described in Section 3.4.2.3 and the viscosity measuring method is

described in 3.4.2.1.

118

10

100

1000

0 10 20 30 40

Visc

osity

(cP)

Time of curing (min)

ARAPOL 25%

ARAPOL 40%

ARAPOL 50%

ARAPOL 68%

Figure 4.4 Viscosity versus time for all ARAPOL/styrene compositions

210

106

64

136

0

50

100

150

200

250

20 30 40 50 60 70 80

Gel

tim

e (m

m)

ARAPOL Volume fraction (%)

Figure 4.5 Gel time versus ARAPOL volume fraction for ARAPOL/MMA composition.

119

28

16.5

12.5

9

10

5

10

15

20

25

30

35

20 30 40 50 60 70 80

Gel

tim

e (m

m)

ARAPOL Volume fraction (%)

Figure 4.6 Gel time versus ARAPOL volume fraction for ARAPOL/ styrene composition.

4.3.2 The effect of MMA/styrene/UPE ratio

MMA is a monomer with a lower reactivity coefficient compared to styrene. It was

used to reduce the initial reaction mixture viscosity and to reduce the curing rate

of the resin (Gan et al., 1994). Comparing the viscosity increase of the curing

MMA/styrene/UPE with that of styrene/UPE shows a further decrease in

viscosity values and viscosity increase rates for the MMA/styrene/UPE with

similar monomer/UPE ratios, as illustrated in Figure 4.7. This enhances the

mixing efficiency with the initiator and promoter, producing a more uniform solid

resin. It also enhances the mixing of the aggregate with the liquid containing the

initial resin components in the PC formulation, by giving more time when the

polymerizing mixture is still a flowing liquid. Gel time increased from 6 minutes

to 210 minutes as MMA increased, as shown in Figure 4.5, while the gel time

increased from 1 minute to 28 minutes as styrene content increased, as shown in

Figure 4.6. The resin gel time outcomes supported the viscosity outcomes. This

120

reduction in viscosity growth rate and increase in gel time in ARAPOL/MMA

compositions qualified the ARAPOL/MMA compositions as being appropriate in

terms of the potential mixing enhancement of the aggregate with the liquid resin

in the PC formulation. It also allows more time when the polymerizing mixture is

still a flowing liquid resin to guarantee the wetting of all aggregates particles and

therefore enhances the PC composite’s mechanical properties.

10

100

1000

0 20 40 60 80

Visc

osity

(cP)

Curing time (min)

ARAPOL 25%

ARAPOL 40%

ARAPOL 50%

ARAPOL 68%

Figure 4.7 Viscosity versus time for all ARAPOL/MMA compositions

121

4.3.3 Exothermic temperature ARAPOL/Styrene compositions

The temperature of resin for ARAPOL/Styrene compositions was measured

according to the method described in Section 3.4.2.1. Figure 4.8 illustrates the

exothermic temperature profile for ARAPOL/styrene compositions. The

ARAPOL/styrene ratio was varied from 20:80 (20% ARAPOL) to 75:25 (75%

ARAPOL), which caused the exothermic temperature to increase from 21.3 – 144.4

°C. In other words, an increase of styrene increases the exothermic temperature. It

is not desirable to have an elevated exothermic temperature as high as 144.4 °C or

103.13 °C, because a substantial increase of exothermic temperature can cause

thermal degradation of resins, the formation of residual stresses and excessive

shrinkage leading to crack formation.

122

0

20

40

60

80

100

120

140

0 20 40 60 80 100

60%ARAPOL/40%Styrene75% ARAPAOL/25%Styrene68% ARAPOL/32%Styrene50% ARAPOL/50 %Styrene20% ARAPOL/80%Styrene

Time (Minutes)

Tem

pera

ture

(°C)

Figure 4.8 Exothermic temperature profile during the curing of ARAPOL/styrene compositions.

4.3.4 Exothermic temperature ARAPOL/MMA compositions

The exothermic temperature profile is relatively lower in ARAPOL/MMA

compositions than in ARAPOL/styrene compositions. Figure 4.9 shows the

exothermic temperature profile for ARAPOL/MMA compositions. Increasing the

ARAPOL/MMA ratio from 25:75 (25% ARAPOL) to 75:25 (75% ARAPOL) elevates

the temperature from 0.5 - 123 °C. The increase in UPE increases the exothermic

temperature while, the increase of MMA decreases the exothermal temperature.

123

Figure 4.9 Exothermic temperature profile during the curing of ARAPOL/MMA compositions.

4.4 Mechanical properties

The mechanical properties were investigated according to the optimization criteria

for PC used for the manufacture of bases of precision tool machinery. All of the

resin compositions were tested, and the resin that complied most fully with the

optimization criteria was deemed the most suitable for the polymeric matrix.

Rheological analysis was required to verify the final determination of the

optimum resin.

124

4.4.1 Damping factor for polymeric matrix

Damping is the energy dissipation properties of a material or system under cyclic

stress. The damping factor is a dimensionless measure describing how oscillations

in a system decay after a disturbance. Many systems exhibit oscillatory behaviour

when they are disturbed from their position of static equilibrium. In DMA the

damping factor is the ratio of the storage modules to the loss modules. A high

damping factor is the primary reason that thermoset resin is used as a binder in

the PC for manufacturing the bases of precision tool machinery. This property

constructs the functionality of damping the unwanted vibration in the bases of

precision tool machinery. The damping factor was measured for all compositions

of ARAPOL/styrene and ARAPOL/MMA using dynamic mechanical analysis

(DMA), except for the 25% ARAPOL/styrene resin composition, because the resin

sample was unsuitable for performing the DMA analysis, as shown in Figure 4.10.

The reason is that increasing the styrene ratio causes a high degree of shrinkage

and fracture in the resin after curing due to internal stresses. This makes it

impossible prepare a sample suitable for assessing the mechanical properties. An

isothermal frequency sweep for a dual cantilever was conducted in the frequency

range of 1-200Hz, as precision tool machine work is in the range of 60-6000 rpm

(Gale, 2008). In addition, the base structural design is a simple supported beam

similar to the DMA experimental set-up. Figure 4.11 illustrates the DMA analysis

of the results for the damping factor versus frequency for all compositions. The

composition with the highest damping factor (tan delta), which was almost

constant is 40% ARAPOL/MMA which reached a damping factor of 0.0458.

125

Figure 4.10 25% ARAPOL/styrene sample.

Figure 4.11 Damping factors of all resin compositions versus frequency plotted using universal V4 software from TA instruments.

Figure 4.12 shows the value of tan (δ) for all resins versus ARAPOL volume

fractions. ARAPOL/styrene composition does not show a trend. With

ARAPOL/MMA, an increase of ARAPOL volume fraction decreased the damping

factor after reaching the maximum at 40% ARAPOL/60%MMA composition. The

126

damping factor decreased rapidly after reaching the maximum, as shown in

Figure 4.12. At higher ARAPOL ratios the weak damping properties are mainly

due to the highly cross-linked UPE network. In the case of resins containing UPE,

MMA and styrene two parameters can contribute to the damping properties of the

cross-linked polymer; (1) the length of uncross-linked segments in the MMA

containing resins, and (2) the degree of cross-linking in both these resins. Higher

ratios of MMA increase the length of the uncross-linked segments in UPE,

increasing the loss modulus in the cross-linked network by allowing for a fraction

of the mechanical energy to be absorbed in the free chain segments while shearing

during the applied strain. This may explain the high damping factor of the

MMA/ARAPOL composition.

40, 0.0175

50, 0.016

68, 0.023

75, 0.021

25, 0.034

40, 0.045

60, 0.0378

75, 0.0218

0.01

0.02

0.03

0.04

0.05

0.06

0.07

20 30 40 50 60 70 80

Tan

(δ)

ARAPOL Volume fraction, %

ARAPOL/Styrene ARAPOL/MMA

Figure 4.12 Damping factor of all resins at frequency of 100HZ, ARAPOL/styrene and

ARAPOL/MMA compositions.

127

4.4.2 Flexural strength

Flexural strength is an essential property for both the resin and the PC composite

system, due to the structural design of the base for a precision tool machine, which

acts as a simply supported beam. The resin with the highest flexural strength

would have a positive reflection on the overall composite material performance,

since resin is the backbone of the PC composite system. The flexural strength

varies according to the amount of ARAPOL in each composition. Figure 4.13

illustrates the effect of ARAPOL volume fraction on UPE resin containing styrene

and MMA on maximum flexural strength. ARAPOL/MMA compositions seem to

have a higher strength than the ARAPOL/styrene compositions. This can be

explained by the increase in the phase separation level as the styrene in

ARAPOL/styrene is increased (Sanchez et al., 2000). The addition of excess MMA

increases the flexural strength of ARAPOL/MMA from 73.7 to 128 MPa when it

reaches the maximum at 40% ARAPOL/MMA, then it decreases even more than

the ARAPOL/styrene. The reactivity coefficient for MMA is lower compared to

styrene which is used initially to reduce the initial reaction mixture viscosity and

reduce the curing rate of the resin (Gan et al., 1994). This situation enhances

mixing initiator and promoter with the composition, and may be the reason for the

ARAPOL/MMA composition having good mechanical properties compared to the

ARAPOL/styrene composition (Rodriguez, 1993).

128

25, 57.4

35, 84.9 50, 85.5

60, 96.775, 90.3

75, 73.7

65, 98.6

50, 113

40, 12825, 119

50

75

100

125

20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0

Flex

tura

l str

engt

h (M

Pa)

ARAPOL volume fraction (%)

ARAPOL/Styrene

ARAPOL/MMA

Figure 4.13 Effect of ARAPOL volume fraction on flexural strength.

4.4.3 Tensile strength

Tensile strength was tested for different resin compositions, and the method is

described in Section 3.4.1.1. Tensile strength was higher for ARAPOL/MMA than

the ARAPOL/styrene compositions at the maximum. The tensile strength of

ARAPOL/MMA followed a similar behaviour to the flexural strength. The highest

strength was reached at 40% ARAPOL/MMA 58.6 MPa, as shown in Figure

4.14(a). The strain was lower for ARAPOL/MMA compositions than for

ARAPOL/styrene, as can be inferred from Figure 4.14(b). The maximum strain

was reached at the same resin composition at which maximum strength was

reached. As shown in Figure 4.14, the strain for the 40% ARAPOL/MMA was

10%, which was low when compared with the same composition of 40%

ARAPOL/styrene, which was 11.5 %.

129

Figure 4.14 Effect of ARAPOL volume fraction on (a) tensile strength, (b) strain for compositions containing MMA and styrene individually.

The modulus of elasticity was calculated. ARAPOL/MMA compositions

demonstrate a higher level in modulus of elasticity than the ARAPOL/styrene

compositions. Increasing ARAPOL or decreasing MMA can increase the modulus

of elasticity at different levels of ARAPOL/MMA composition. Increasing the

ARAPOL can increase the modulus of elasticity of ARAPOL/styrene

compositions, except for the last point in 75%ARAPOL/styrene composition,

which reduced rapidly as it was the lowest, as is shown in Figure 4.15.

130

531.75

601617

631

480

707

759 769758

782

450

500

550

600

650

700

750

800

850

20 30 40 50 60 70 80 90 100

Mod

ulus

of e

last

icity

(M

Pa)

ARAPOL volume faction (%)

Aropol/Styrene

Aropol/MMA

Figure 4.15 Effect of ARAPOL (%) on modulus of elasticity for ARAPOL/Styrene and ARAPOL/MMA.

4.4.4 Coefficient of thermal expansion (CTE) for polymeric matrix

The most sensitive thermal property for a resin binder in PC is the CTE, which has

a direct effect on precision tool machine accuracy. CTE is the key to control the

behaviour of the PC base deflections, under thermal conditions, in the operational

environment of the bases for precision tool machinery. The first order

approximation of CTE in PC, as a composite, can be obtained using the mixing

rule (Wong and Bollampally, 1999). This relationship can describe the influence of

CTE resin on over all PC CTE.

)1.4.(..................................................).........1( φαφαα −+= mac

131

where cα , mα , and aα are the CTEs of the composite, matrix resin , filler aggregate,

and φ is the volume fraction of the aggregate respectively. The CTE of the

polymeric matrix is usually the highest compared to the CTE of aggregates. In PC,

the CTE of the mortar resin is usually 7 to 10 times higher than the CTE of the

aggregate. Lowering the resin CTE to closer to that of the aggregate and other

components such as cast iron inserts in the PC bases of precision tool machines

produces a more homogeneous composite with uniform thermal expansion and

less thermal stress, since CTE follows the rules for a mixture of composite material

(Bruck and Rabin, 1999). CTEs were measured for numerous resin compositions of

ARAPOL/styrene and ARAPOL/MMA at various proportions. Figure 4.16 shows

resin samples prepared for CTE testing.

Figure 4.16 Resin samples with various proportions of MMA, ARAPOL and styrene prepared for measuring CTE.

Figure 4.17 and Figure 4.18 show the different thermal expansion behaviours for

all compositions with linear behaviour in various grades.

132

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0 20 40 60 80 100

ARAPOL 25%ARAPOL 40%ARAPOL 50%ARAPOL 68%ARAPOL 75%

Elon

gatio

n(m

m)

Temperature (°C)

Figure 4.17 Thermal expansion behaviour of different resins with different proportions of ARAPOL/MMA.

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0 20 40 60 80 100

Elon

gatio

n (m

m)

T emperature(°C)

ARAPOL 40%

ARAPOL 50%

ARAPOL 68%

ARAPOL 75%

Figure 4.18 Thermal expansion behaviour of different resins with different proportions of ARAPOL/styrene.

133

These figures (Figure 4.17 and Figure 4.18) were used to calculate the CTE

according to the method described in Section 3.4.1.3, in order to produce a clearer

image of the behaviour of all compositions in relation to CTE. The CTE of all the

compositions increased as ARAPOL volume fraction increased, as illustrated in

Figure 4.19. This is due to the high CTE of the UPE in ARAPOL (67%).

ARAPOL/MMA compositions have lower thermal expansion than

ARAPOL/styrene compositions. This is consistent with reports of low CTE for PC

with polymethyl methacrylate as binding resin (Blaga and Beaudoin, 1985). The

thermal expansion of styrene-rich resin is higher due to the higher molecular

packing factor in these resins, leaving only a small space for molecular expansion

at increasing temperatures. The inclusion of MMA in the resin composition

increases the spatial disorganization and lowers the molecular packing factor,

allowing for the polymer chain expansion to be accommodated in the free space

existing in the cross-linked network of the resin.

8.56

9.3

10.2510.56

6.93

7.98

8.99 9.35

9.02

6

7

8

9

10

11

20 30 40 50 60 70 80

ARAPOL/Styrene

ARAPOL/MMA

α ×10-5 (1/°C-1)

ARAPOL volume fraction( %)

Figure 4.19 CTE for all resin composition versus ARAPOL volume fraction (%).]

134

4.4.5 Hardness

Hardness was measured for a variety of resin compositions, according to the

method described in Section 3.3.2. Figure 4.20 illustrates the relationship between

ARAPOL volume fraction and Shore D hardness. Generally, it is reasonable to say

that an increase in the ARAPOL volume fraction can decrease the hardness in the

ARAPOL/MMA composition.

86.675

85.8585.1

85.875

84.55

80

81

82

83

84

85

86

87

88

89

90

25 40 50 60 75

Har

dnes

s Sh

ore

D

ARAPOL volume fraction (%)

Figure 4.20 ARAPOL volume fractions versus hardness shore D in ARAPOL/MMA composition.

An increase in the volume fraction of ARAPOL does not indicate a trend in

hardness Shore D for ARAPOL/Styrene compositions. The fluctuation in the

increase and decrease of hardness Shore D with an increase in the ARAPOL

volume fraction is shown in Figure 4.21.

135

81.175

85.8585.45

86.775

83.675

80

81

82

83

84

85

86

87

88

89

90

25 40 50 68 75

Har

dn

ess

Sh

ore

D

ARAPOL volume fraction (%)

Figure 4.21 ARAPOL volume fractions versus hardness shore D in ARAPOL/Styrene composition.

4.5 Conclusions

The composition with the highest damping factor of all the resins had 40%

ARAPOL/MMA, which has a damping factor of 4.56%. The highest flexural

strength was reached with the 40%ARAPOL/MMA composition, with 128 MPa

and a low strain of 10%, as compared with the 40%ARAPOL/styrene, which was

11.5 %. The lowest CTE was achieved with 25% ARAPOL/MMA (6.93×10-5 °C-1),

followed by 40% ARAPOL/MMA (7.98×10-5 °C-1). The module of elasticity of the

40% ARAPOL/MMA was 759 MPa. The highest Shore D hardness for

25%ARAPOL/MMA was 86.6 and 85.5 for 40%ARAPOL/MMA. The result of the

mechanical properties shaped the focus for the rheological analysis of the

ARAPOL/MMA compositions, although the ARAPOL/styrene compositions

136

were not ignored. The effects of the UPE/styrene ratio in the ARAPOL/styrene

and the UPE/MMA/styrene ratios in the ARAPOL/MMA composition were

studied. It was concluded that the ARAPOL/MMA compositions were more

suitable for consideration, since the mixing efficiency with the initiator, and the

promoter produced a more uniform resin. In addition, it may also enhance the

mixing of the aggregate with the liquid resin by allowing more time when the

polymerizing mixture is still a flowing liquid. The exothermic temperature profile

was relatively lower in the ARAPOL/MMA compositions than the

ARAPOL/styrene composition. The lowest composition in terms of exothermic

temperature and viscosity was the 25% ARAPOL/MMA, followed by the

40%ARAPOL/MMA. The mechanical properties of 25% ARAPOL/MMA were

very low compared to the 40%ARAPOL/MMA. This resulted in the nomination of

the 40%ARAPOL/MMA as the optimum binder for the PC use in the

manufacturing of bases for precision tool machinery. It meets most of the

optimisation criteria at a good level, while other resins met fewer of the

optimisation criteria and failed some. Table 4.1 shows a comparison of the

optimized resin with the published data on epoxy and UPE with various

monomeric combinations. The epoxy mechanical properties are better than those

of the UPE, as stated in Chapters 1and 2. The average viscosity is very low

compared to published data for both epoxy and UPE, as shown in Table 4.1, which

is an advantage that can be used to enhance the mixing process when the resin is

mixed with aggregates to obtain an PC composite with good mechanical

properties. The reason for this is that the low viscosity of MMA is lower than

water viscosity. In addition, the CTE of epoxy is less than the CTE of the

optimized resin.

137

Table 4.1 comparison of the published data for epoxy and UPE with the

optimized resin

Property The

optimized resin

Epoxy from published literature

References UPE from published literature

References

Damping ratio

0.045 0.134 (Wang et al.,

2008) 0.053 (Ray, 2009)

Tensile strength MPa

58.6 40-90 (IDES, 2013) 4.1-90 (IDES,

2013)

Flexural strength ,

MPa

128 90-145 (IDES, 2013) 60-160 (IDES,

2013)

Viscosity, poise

1.5 (average ) 20 (Vipulanandan

and Paul, 1990) 40

(Vipulanan

dan and

Paul, 1990)

CTE, I/°C 7.93×10-5 12×10-6 (McKeown and

Morgan, 1979)

138

Chapter 5

5 Optimization of the polymer concrete filler

composition system

5.1 Introduction

In this chapter damping properties, flexural strength and the CTE of PC are

investigated for various PC filler compositions. These properties are the main

parameters that can affect the accuracy of precision tool machines and the strength

of the PC base. Six fillers (basalt, spodumene, fly ash, river gravel, sand and chalk)

have been studied. PC samples were prepared with different compositions of

aggregates containing the same resin volume fraction (aggregate 83% and resin

17%). A four-point flexural test was used to measure the flexural strength of the

PC samples. The CTE for PC was measured using an in house custom-built device.

The preliminary optimum composition with the highest flexural strength and the

lowest CTE, was found to be basalt, spodumene and fly ash. The basalt, sand and

fly ash composition was the second best. This second composition was considered

for further optimization in terms of the resin volume fraction because of its ability

to adopt a smaller amount of resin. Different samples of PC were prepared with a

variety of resin volume fractions: 17%, 15% and 13%. The resin volume fraction

139

was demonstrated to have a significant effect on the CTE and flexural strength of

PC. The effect of the resin volume fraction on the PC damping ratio was identified.

It was found that 40% of the reduction in the PC structural damping ratio was due

to the PC resin volume reduction of 4% (17-13%). The final optimized composition

was basalt, sand and fly ash (filler 87% and resin 13%). ANSYS 13.0 software was

employed to visualize the influence of PC compositions on the thermal expansion

of the base and to show how it affected the level of precision of the tool machine.

5.2 Particles properties of aggregates

The aggregates’ true density, ρTrue (g/cm3) was measured using a pycnometer,

and their bulk density ρbulk (g/cm3) was measured using a measuring cylinder.

All methods have been described in Sections 3.3.3 and 3.3.4, respectively. The

packing factor, (VP), was calculated based on the ratio of the obtained true and

bulk densities. The fine aggregate (chalk, fly ash) particle size distributions were

obtained using a laser scattering method facilitated by a Mastersizer X (Malvern

Instruments, USA). Middle and coarse aggregate size distributions were obtained

using sieve analysis. These methods were described in Sections 3.3.1 and 3.3.2,

respectively. Figure 5.1 shows the particle size distributions for all aggregates. The

BET (Brunauer, Emmett and Teller, 1938) active specific surface area of the

aggregates was determined by nitrogen gas adsorption/desorption. The nitrogen

sorption measurements were performed using Micromeritics ASAP 2010 (USA).

The adsorption and desorption isotherms were recorded using an 89-point

pressure table with 15 second equilibration intervals. The method is described in

detail in Section 3.3.5.

140

Figure 5.1 Particle size distributions for all aggregates.

Table 5.1 summarizes the measured aggregate properties and referenced

aggregate properties, such as CTE (αs,°C-1), for each filler (Brandt, 1988, Hummel,

1950).

141

Table 5.1 Properties of all sizes of aggregates: coarse, middle and fine filler.

Material ρBulk

(g/cm3)

ρTrue

(g/cm2)

Vp

(%)

CTE Aggregate

(°C-1)

BET

(m2/g)

Gravel 1.63 2.61 62 11.2×10-6 (Brandt, 1988) 0.12

Basalt 1.6 2.77 58 5.5×10-6 (Brandt, 1988) 0.22

Spodumene 1.56 2.879 54 2.5×10-6 (Hummel, 1950) 0.10

Sand 1.71 2.63 64 11×10-6 (Brandt, 1988) 0.29

Chalk 1.35 2.69 50 10×10-6 (Brandt, 1988) 1.60

Fly ash 1.33 2.71 49 5.2×10-6 (Brandt, 1988) 1.02

The composition aggregate proportions were calculated using the Furnas method

(Furnas, 1931). According to this method, the aggregate number of generations for

particles is obtained based upon the ratio (K) of the biggest particle diameter and

smallest particle diameter. The diameter ratio was calculated using data from

Figure 5.1 and the volume of voids, which is equal to 100 - Vp (%). Vp can be seen

in Table 5.1. Table 5.2 shows the average diameters of the biggest and smallest

particles for each aggregate.

142

Table 5.2 Aggregate average diameters and volume voids.

Aggregates Equivalent

diameter, (μm)

Volume

voids (%)

Gravel 6150 38

Basalt 6570 42

Sand 335 36

Spodumene 328 46

Chalk 18.5 50

Fly ash 31 51

The K ratio for each composite is shown in Table 5.3. The number of generations

obtained was 2.5-2.7 by using Figure 5.2. The number of generations must be in an

integral number format according to Furnase method. The closest integral number

to the number of generation obtained is 3. Three generations were therefore used

for each composition.

143

Table 5.3 Ratios (K) of average smallest diameters to largest diameters for potential compositions.

Aggregates K

Gravel/ Fly ash 0.005

Basalt/ Chalk 0.0047

Gravel /Chalk 0.003

Basalt/ Fly ash 0.0028

Figure 5.2 Recommended number of generations as a function of packing and ratio K.

In Furnas theory, the ideal particle shape is assumed to be spherical (Furnas, 1931).

The void volume fraction for three generations of particles can be obtained by

applying K (0.0028 - 0.005) and the number of generations using Figure 5.3.

144

Figure 5.3 Theoretical packing of particles versus the ratio of smallest to largest generations.

The volume of voids was within the range of 16 - 17 % in PC composition.

According to the Furnas method, the diameter of the intermediate generation, D2,

can be calculated using the following expression:

)1.5.(............................................................312 DDD =

where D1 and D3 are the biggest and the smallest diameter of particle generations.

D2 is calculated for all compositions as shown in Table 5.4.

145

Table 5.4 Intermediate generation for the compositions.

Compositions Intermediate generation D2 (μm)

Gravel/ Fly ash 451.3

Basalt/ Chalk 348.6

Gravel /Chalk 337.3

Basalt/ Fly ash 451.3

All the intermediate generations, D2, is bigger than both of the sand and

spodumene largest particle sizes. The largest particle sizes of sand and spodumene

were (335, 400 μm), as shown in Figure 5.1. This indicates that both spodumene

and sand are suitable for any composition. The total absolute volume of fillers 0V

can be calculated using the following formula:

)2.5...(............................................................111

1

3

2

2

2

1

10 V

VV

VV

V+

++

++

=

Where V1, V2 and V3 are volumes of voids for the largest, intermediate and the

smallest generations respectively. The relative volume of voids can be calculated

using 1-Vp.

146

Table 5.5 Total absolute volume of fillers for each composition.

Compositions Absolute volume of all fillers, 0V

Basalt/ spodumene/fly ash 1.132

Basalt/spodumene/chalk 1.133

Basalt/ sand/fly ash 1.098

Basalt/ san/chalk 1.1

Gravel/sand/fly ash 1.089

Gravel /sand/chalk 1.090

Gravel/spodumene/fly ash 1.125

Gravel /spodumene/chalk 1.126

The total volume fraction occupied by the solid particles fV can be calculated using

the following formula:

)3.5.........(..................................................).........1( 210 VVVf −=

147

Table 5.6 Theoretical total volume fraction of solid for each composition.

Compositions Total volume of solid fillers, Vf, (%)

Total volume of void

(1-Vf),(%)

Basalt/ spodumene/fly ash 93.2 6.8

Basalt/spodumene/chalk 93.3 6.7

Basalt/sand/fly ash 90.4 9.6

Basalt/san/chalk 90.5 9.5

Gravel/sand/fly ash 93.1 6.9

Gravel /sand/chalk 93.3 6.7

Gravel/spodumene/fly ash 96.2 3.8

Gravel /spodumene/chalk 96.3 3.7

The volume fraction of each aggregate component Pi can be calculated using the

following formula:

)4.5....(............................................................) (PioV

Vi=

Where Vi is the packing fraction of individual aggregates that can be obtained

from Table 5.1. oV is the absolute volume of each composition and can be obtained

from Table 5.5.

Equation 5.4 can be rewritten as follow:

148

)5.5...(......................................................................) (Pio

p

VV

=

Table 5.7 Volume fraction for each aggregate within its composition for all compositions.

Compositions Volume fraction of each aggregate (%)

Basalt/ spodumene/fly ash 51 , 47, 2

Basalt/spodumene/chalk 51, 47, 2

Basalt/ sand/fly ash 52, 38, 10

Basalt/ san/chalk 52 , 38, 10

Gravel/sand/fly ash 53, 38, 10

Gravel /sand/chalk 53 , 37, 10

Gravel/spodumene/fly ash 55, 35, 10

Gravel /spodumene/chalk 55 , 35, 10

This approach takes into account the volume of voids and provides a good

indication of possible filler compositions (Furnas, 1931). However, it does not take

into account particle shape and is to be used mainly for spherical bodies. Another

approach is based on the wetting of the particle surface (Michaylov, 1989).

According to this approach, the volume of resin can be identified using the

following expression:

)5.5.......(..................................................)( 2211 rrr KVSVSVV ηδο +=

149

where Si is the specific surface area of aggregates, δr is the thickness of resin (1.5 -2

μm), K is a constant = 1.05 and ηr is the relative viscosity at the temperature of

moulding with a reference temperature of 20°C. The smallest aggregates are not

taken into account (Michaylov, 1989). The main problem with this approach is that

it does not take into account voids between aggregates.

Theoretical calculations can provide valuable information about the composition

of solid filler in terms of better packing. However, the volume fraction of the

mortar can be identified only after a set of trial tests on the PC materials. The

results obtained by using the Furnas method were implemented as a start in the

trial procedure. Numerous trials were run to obtain the aggregate composition

and the amount of resin that keep the resin surfaced for all the composition

samples at the end of the moulding operation. It was found that the best aggregate

proportions for the PC mixture were as follows:

Fine aggregate 8.3%, coarse aggregate 49.8%, middle size aggregate 24.9% (v/v)

and 17% (v/v) resin. The preparation of the sample of PC was described in Section

3.5.1.

5.3 Thermal expansion of composite material

When heat is applied to a material, there is a change in temperature T1 → T2 with

a corresponding change in volume V1 → V2. If the difference between

temperatures is small, the change in volume is in direct proportion to the

temperature change by a coefficient, β, which is called the coefficient of volumetric

thermal expansion. The corresponding coefficient for the linear case is the

150

coefficient of the linear thermal expansion, α. If the substance is isotropic, the

relationship between linear and volumetric coefficients of thermal expansion is as

follows: β=3α (Touloukian, 1977). Thermal expansion of any composite material in

general, where filler is dispersed in a matrix, depends upon the following factors

(Touloukian, 1977, Chawla, 1988):

Thermal expansion of matrix, αm

Thermal expansion of dispersed filler, αf

Volume fraction of filler or matrix, Vf, Vm

Isothermal bulk modulus of filler, Bf

Isothermal bulk modulus of matrix, Bm

Shear modulus of matrix Gm

The component is considered to be incompressible, when Bf and Bm values are

infinite. The coefficient of thermal expansion for a composite material cα may be

determined using the rule of mixture (Chawla, 1988, Touloukian, 1977) according

to the following expression:

)6.5.........(........................................).........1( fmffc VV −+= ααα

It seems that the reduction of CTE of the matrix and filler reduces the CTE cα of

the composite material. In addition, the volume fractions of resin and filler have

an effect on cα . To reduce the CTE of PC, an experiment in each direction was

151

feasible. However, the one with the highest feasibility was the resin reduction,

since the resin is the component that has the highest CTE (7.98 ×10-5 °C-1).

5.4 Results and discussion

Aggregate surface morphology, particle size distribution, voids and resin volume

fraction are synergic and fatalistic parameters in governing the thickness and

shape of interfacial adhesion bonding (IAB) between PC particles. The main driver

of the thermal and mechanical properties of PC such as CTE and flexural strength

is the interfacial adhesion bonding between particles. The thermal properties of

particles and aggregate proportions affect the overall CTE of PC (Xu et al., 1994).

Figure 5.4 shows a PC sample demonstrating the failure mechanism that went

through the interfacial adhesion bonding between filler particles, i.e. the polymeric

matrix.

Figure 5.4 SEM of failed PC sample: the failure mechanism is going through the interfacial bonding between filler particles, in this case fly ash.

152

Eight compositions were investigated and compared in order to select the one

with the highest flexural strength and the lowest CTE. Figure 5.5 shows PC

samples for all compositions.

Figure 5.5 Samples of polymer concrete of different compositions.

The preliminary suggestion of optimum composition for a precision machine base

application was basalt, spodumene, and fly ash, as shown in Table 5.8. The

flexural strength was 22.85 MPa, due to the fact that crushed basalt increases the

flexural strength of concrete (Kilic et al., 2008), basalt surface contains rough

textures (rough surface) due to the crushing process. Fly ash also increases the

flexural strength of polymer concrete (Rebeiz and Craft, 2002).

153

Table 5.8 Aggregate compositions used in the PC formulations in this study and their flexural strength and CTE.

Spodumene, which comes from lithium mining, has textures attributable to the

mining process. Figure 5.6(a) shows spodumene particles indicating that the

microstructure of spodumene is in the form of crystallite layers (J.Graham, 1975).

The layers may partially separate to some extent at the beginning and the end of

the layer during mixing. This allows the mixture of fly ash-resin to flow between

the spodumene layers, basalt textures and microspore cavities, since fly ash is the

first filler mixed with the resin. Spodumene and basalt are then added to the PC

mixture. This condition results in higher adhesion bonding between the polymeric

matrix and the aggregates.

No. Compositions Flexural Strength

(MPa)

Deflection

(mm)

CTE

(°C-1)

1 Basalt, spodumene, fly ash 22.85 1.458 10.0×10-6

2 Basalt, sand, fly ash 22.41 1.05 14.9×10-6

3 Basalt, spodumene, chalk 21.57 1.007 10.3×10-6

4 Basalt, sand, chalk 20.05 1.00 16.1×10-6

5 Gravel, sand, fly ash 18.92 0.94 14.6×10-6

6 Gravel, spodumene, chalk 18.22 0.90 12.6×10-6

7 Gravel, spodumene, fly ash 16.27 0.97 12.5×10-6

8 Gravel, sand, chalk 16.92 0.92 18.8×10-6

154

Figure 5.6 SEM images of (a) Spodumene: with hard and sharp textures containing layers, (b) Sand: round and smooth, (c) Fly sh: spherical shape and smooth surface, (d) Chalk: irregular shape with texture.

In addition, fly ash particles have a spherical shape, a smooth surface and a micro

size, as shown in Figure 5.6(c). This leads to low viscosity at the time of mixing

the fly ash with the resin, as compared to chalk, as illustrated in Figure 5.7. This

indicates the high flow ability and filling capability of the fly ash-resin mixture.

The basalt texture and the layers of spodumene facilitate the formulation of a

highly adhesive interfacial bonding between the polymeric matrix and the

aggregate. This is a possible explanation for the high flexural strength of the first

composition.

155

Figure 5.7 Viscosity of mixture resin fly ash, resin chalk versus time.

The first composition scored the lowest of CTE, 10.0×10-6 °C-1. All aggregates have

a low CTE (Hummel, 1950, Brandt, 1988), and the lowest value is spodumene, as

shown in Table 5.1. The flexural strength of the second composition (basalt, sand

and fly ash) was 21.41 MPa. Sand has a higher BET active surface area than

spodumene, as shown in Table 5.1, and less textural roughness on the surface, as

shown in Figure 5.6(b). In addition, there are no layers in the microstructure of the

sand particles to give extra grip, which may be the reason for the slightly reduced

flexural strength. The second composite had a higher CTE, by approximately 50%,

than the first. This is due to the sand CTE effect, which is almost three times more

than the spodumene CTE and two times more than the fly ash CTE, as shown in

Table 5.1. The main reason for the reduced flexural strength in the third

composition (basalt, spodumene and chalk) is that the chalk particles have a more

active surface area than fly ash, as shown in Table 5.1. This indicates that more

resin is required for efficient wetting. Furthermore, the chalk resin mixture

156

provides less flow ability and filling capability than the fly ash resin mixture, as

shown in Figure 5.7. The reason for this is the irregular shape of the chalk particles

and the number of sharp corners (rough surface), as shown in Figure 5.6(d). This

results in higher viscosity during the mixing, which leads to the formation of a

lower adhesive bonding mechanism on the surface of the aggregates compared to

fly ash. This level of gripping adhesion leads to a reduction of the flexural

strength. The CTE for the third composition is close to the first composition, due to

the presence of spodumene, which has the lowest CTE, as shown in Table 5.8.

The fourth composition (basalt, sand and chalk) suffers because of the chalk and

sand that both share responsibility for low flexural strength and high CTE, for the

reasons explained previously. Replacing basalt with river gravel in the fifth

composition results in a reduction in flexural strength. River gravel has a smaller

BET surface area and a smoother surface than basalt, which may be the reason for

less adhesion and a reduction in flexural strength. River gravel increases the CTE

of the fifth composition, as shown in Table 5.8. It has a higher CTE than other

aggregates, as shown in Table 5.1.

The presence of river gravel, chalk and sand in a PC composite system reduced the

flexural strength and increased the CTE at various levels for different

compositions. This condition was due to the CTE of the particles, as well as their

morphology, and may have resulted in an interfacial bonding that had less

adhesion between particles than basalt, spodumene and fly ash composition.

157

The second composition was nominated for further optimization in terms of resin

volume fraction. This step was owing to its ability to accommodate a resin volume

fraction of less than 17%. The reason is that sand has a high packing volume due

to its rounded particle shape. In addition, the particle shape of fly ash is spherical

have high compaction. Figure 5.8 shows the effect of a reduction in the resin

volume fraction on the CTE of PC.

Figure 5.8 CTE of PC composite versus resin volume fraction.

Decreasing the resin volume fraction results in a decrease in the CTE of PC, since

the resin has the highest CTE (7.98 ×10-5 ºC-1) in PC components. It was noticed

that the layer thickness of segregated fine aggregate, which appears in the upper

level of the sample during the PC sample vibration process, is affected by the resin

volume fraction in PC. Figure 5.9 reveals that increasing the volume fraction of the

158

resin will increase the layer thickness of the segregated fine aggregate-resin

mixture.

Figure 5.9 Layer thickness of segregated fine aggregate for different resin volume fraction.

PC composite follows the rule of mixture regarding composite mechanical

properties. Reducing the resin by 4% reduced the CTE of PC by approximately

31%. The other side effect of resin reduction is flexural strength. Figure 5.10

demonstrates that a reduction in the amount of resin by 4% reduces the flexural

strength by approximately 36%. This is because the amount of resin that fulfils the

interfacial adhesion bonding (IAB) between particles is reduced (Knab, 1972). The

lowest flexural strength is 13 MPa for 13%, which is still acceptable for building a

base. The base cross-section is sufficient to cope with the relatively low flexural

stress, considering the small machine weight in comparison to the base size.

159

10

15

20

25

30

12 14 16 18

Flex

tura

l Stre

ngth

(MPa

)

Resin volume Fraction (%)

Figure 5.10 Flexural strength of PC versus resin volume fraction.

5.5 Effect of resin volume fraction on polymer concrete damping

To identify the effect of the resin volume fraction on the PC damping ratio, a

structural damping test was conducted in order to provide an indication of the

damping ratio of a structural system that contains a PC sample which occupies 80-

90% of the experimental system. A tap test was conducted for PC samples

composed of basalt, sand and fly ash containing 20, 17, 15 and 13% resin volume

fractions. The method of testing was described in Section 3.6.4. A PC sample

containing 20% resin volume fraction was added for the purpose of elucidating the

effect of resin on the damping ratio of the PC. Figure 5.11 shows the time domains

for different samples of PC with 17, 13, and 20% resin volume fractions.

160

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5 2Ampl

tude

(µm

)

Time (S)

Resin 13%

Resin 20%

Resin 17%

Figure 5.11 Time domain for different PC samples containing 13, 17 and 20% resin volume fraction.

The damping ratio was calculated for 12 PC samples according to logarithmic

decrement analysis (LDA), as described in Section 3.6.4. Each set of four samples

had a different amount of resin. Figure 5.12 shows the damping ratio for each set

at the same time. The results indicate that the amount of resin is the main key

control in relation to the damping ratio of PC.

161

0.033

0.037

0.042

0.0230.025 0.026

0.0120.014

0.016

0.011 0.012 0.0114

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

Dam

ping

ratio

Sets of PC samples

20% resin17% resin15% resin13% resin

Figure 5.12 Effect of the amount of resin polymer concrete on the structural damping system.

The results indicate that approximately 40% of the reduction in the structural

damping ratio is due to the PC resin volume reduction of 4% (17-13%). These

results do not represent the material damping ratio of PC as a material property,

but provide an indication of the effect of the amount of resin in a PC composite on

the structural damping ratio of the experimental system. This result is consistent

with other research that used epoxy as a resin binder in a composite material (Bai

et al., 2009).

5.6 Results validation

To have a realistic understanding of the effects of filler compositions and resin

volume fraction on the base, CAE software ANSYS 13 was adopted. The software

was also used to reveal the effects of optimized properties on the functional

performance of the PC base in relation to the precision tool machine accuracy level

162

within the boundary of a thermal load obtained from an industrial environment.

Figure 5.13 shows the CAD model of a CNC grinding tool machine. The CAD

model was used including the frame, the main part of headstock and the main

servomotor. The mass point feature in ANSYS 13.0 was utilized to avoid any

complications that might arise during the analysis due to assembly complexity. It

was also used to show the effect of all machine components on the base without

considering assembly issues.

Figure 5.13 CAD model of a CNC grinding tool machine and the base, in transparent mode, demonstrating insert supports using yellow arrows.

The mass point feature allows the effect of heavy components on the precision tool

machine base, without having a complex assembly in the CAD model during the

simulation. Figure 5.14 shows centroid determinations for each assembly group

individually.

163

Figure 5.14 Centroid determinations for each individual group of components (tagged by red).

A centroid of each sub-assembly, linked to the contact area of the base using the

mass point feature at two mass points (A-600 kg and B-300 kg), is shown in Figure

5.15.

Figure 5.15 The main mass point to be included in the simulation.

164

Figure 5.16 shows the outlet coolant, inlet coolant and environment temperatures

during the time of operation for the base of a CNC grinding tool machine. The

method of measuring temperature was the same as that used in monitoring the

temperature profile for the resin, which is described in Section 3.4.2.2. The framed

area in Figure 5.16 was selected as the boundary condition at the peak point for

the environmental temperature (24.8 °C) and outlet coolant temperature (22.3 °C),

to be taken from the frame and applied as a boundary condition in the simulation.

Figure 5.16 Outlet, inlet and environment temperatures versus time under operational conditions for a CNC grinder tool machine.

The environmental temperature was 24.8 °C when applied to the outside of the

base and the coolant outlet temperature was 21.5 °C and applied on the inside of

the base where the water splashed on the base after cooling the tool in the

grinding operational conditions. Figure 5.17 shows the temperatures and the areas

that were applied.

165

Figure 5.17 Temperatures and the areas where they were applied on the base.

The temperature distribution on the base was obtained using steady-state thermal

analysis in ANSYS 13.0 CAE software, as shown in Figure 5.18.

Figure 5.18 Temperature distribution on the base of the CNC grinder tool machine.

166

Constraints were applied to the stands where the machine was fixed to the

ground. Material was assigned according to the material properties. Structural

analyses under thermal conditions were run using ANSYS 13.0, and Figure 5.19(a)

illustrates the directional structural deformation (Z-direction) of the base for the

first composition (basalt, spodumene, fly ash). The thermal conductivity, which

could not be measured, was obtained from the literature 2.8 (w/mk) (Demirboga

and Gul, 2003). It was expected to be very close to the PC material. The modules of

elasticity obtained from the compression test were 14.6 GPa, the compression test

being in accord with AS12002.9-1986, as described in section 3.5.2. The most

effective part of the base is the rails that hold the moving components and are an

essential part of the guiding system of the CNC grinder tool machine in the

operational environment. Maximum deformation was 25 μm on the wall base,

concentrated on an ineffective component (in terms of precision performance),

which is a small portion of the base located on the walls (approximately 2% of the

base). The variation in deformation of the rails on one side was approximately 2

μm. The variation in deformation between the two sides of the rails was

approximately 0.1 – 0.5 μm. The last composition in ranking: river gravel, sand

and chalk, had almost double the thermal expansion compared to the first

composition, as shown in Table 5.8. Figure 5.19(b) exhibits the directional

deformation on the base containing the last composition. Maximum deformation

is 45.5 μm and 75 % of the upper half of the base has been deformed nearest to the

maximum. Variations in deformation on the rails are 3 – 5 μm. Variations in

deformation between the two sides of the rails are approximately 1 – 3 μm.

167

Figure 5.19 Structural deformations under thermal conditions (a) first composition (basalt, spodumene, and fly ash), (b) last composition (gravel, sand, chalk).

Figure 5.20(a) shows that the directional structural deformation of the base for the

second composition (basalt, sand, fly ash, resin volume fraction is 17%), and the

maximum deformation in Z direction is 30.2 μm. Rail variations on one side are 1.5

– 2 μm. Variations in deformation between two sides of the rails are 0.2 – 0.34 μm.

Figure 5.20 Structural deformations under thermal condition (a) PC resin amount 17% (b) PC resin amount 13%.

168

Figure 5.20(b) exhibits the directional structural deformation of the base for the

composition (basalt, sand and fly ash) with a 4% reduction in resin volume

fraction. The maximum deformation in Z direction for the base is 18 μm. Rail

variations are 0.13 – 0.34 μm. Variations in deformation between the two sides of

the rails are 0.011 – 0.06 μm. These variations are the smallest, and hence can be

ignored, since they are less than 1 μm for both one side and two sides of rails

variations in deformation. Table 5.9 illustrates all measurements in one domain for

a clear comparison.

Table 5.9 Effect of PC composition, resin volume fraction on precision of the base

5.7 Conclusions

The utilization of aggregate morphology, and the thermal and mechanical

properties of particles, resulted in an optimum PC being obtained for the base of a

precision machine. In conclusion:

Compositions Resin volume fraction

(%)

Maximum deflection

(μm)

Variation in deformations on the rails in one

side (μm)

Variation in deformations between two sides of rails

(μm)

Basalt, spodumene, fly

ash

17 25 2 0.1-0.5

Gravel, sand, chalk 17 45.5 3-5 1-3

Basalt, sand, fly ash 17 30.2 1.5-2 0.2-0.34

Basalt, sand, fly ash 13 14.6 0.31-0.13 0.11-0.06

169

§ The optimum composition is basalt, sand and fly ash (87% filler and 13%

resin), which has the lowest CTE and acceptable flexural strength.

§ A reduction in resin diminishes the negative effect of sand in relation to the

final CTE and the resulting flexural strength is acceptable for the

application.

§ A reduction in resin by 4% from 17% down to 13% reduces the damping

ratio by a 40% reduction of the structural damping ratio of PC.

§ When any aggregate of the optimum composition is replaced with another

aggregate (gravel, sand and chalk), it results in the PC composition

suffering a further reduction in flexural strength with an increase in CTE.

The main reason for this was that the morphological and thermal

properties of particles affect the interfacial adhesion bonding behaviour in

the PC composite system.

§ The optimum composition is extremely cost-effective compared to the first

composition. Sand is 90% less expensive than spodumene and a 4% resin

reduction reduces the cost of the composite by more than 4%. Resin is the

most expensive component in a PC composite system.

§ Based on simulation studies, the optimum composition reduce the

variations in deformation of rail bases to a sufficiently low level for them to

be ignored. This enhancement of the operational conditions for precision

tool machinery improves the level of precision and achieves more precise

products.

Comparing the damping ration of optimized PC with cast iron which is 0.418

%(Orak, 2000) it was found that the optimized PC higher than cast iron by 6 times

approximately.

170

Table 5.10show a comparison of the optimized PC with the published data of PC-

epoxy based and PC-UPE the properties of PC -epoxy is higher than the PC-UPE

but the PC-epoxy is quite expansive compared to PC-UPE. In addition the

property of optimized PC is better than PC –UPE published data.

Table 5.10 comparison of the published data for PC-epoxy based and PC-UPE based

with the optimized PC.

Property The

optimized PC

PC-Epoxy from

published literature

References PC-UPE from

published literature

References

Damping ratio,%

2.4 4.36–5.34 (Li et al.,

1996) 2.21

(Cortés and

Castillo, 2007)

Flexural strength ,

MPa

22.41 50 (Czarnecki,

1993) 15 (Czarnecki, 1993)

Property The

optimized PC

PC-Epoxy from

published literature

References PC-UPE from

published literature

References

Damping ratio,%

2.4 4.36–5.34 (Li et al.,

1996) 2.21

(Cortés and

Castillo, 2007)

Flexural strength ,

MPa

22.41 50 (Czarnecki,

1993) 15 (Czarnecki, 1993)

171

Chapter 6

6 Optimization of moulding technology

6.1 Introduction

Aspects of moulding technology have a great effect on the quality and

productivity of the polymer concrete used to manufacture the base of precision

tool machine. In this chapter, the results and the analysis are both presented of an

experimental investigation on the effects of moulding technology on mechanical

strength and maturity of polymer concrete. Those aspects are as follows:

§ Effect of voids population on compressive strength of polymer concrete.

172

§ Influence of DMA amount and moulding temperature on maturity, mixing

process and the strength of matrix domain.

§ Mixing technology and its influence on mechanical properties of PC.

Enhancing certain aspects of moulding technology could lead to an elevation of

the mechanical strength of PC that may assist in producing PC with a high level of

compliance with the optimisation criteria for PC used in manufacturing bases for

precision tool machinery.

6.2 The effect of the number of voids on the compressive strength

of polymer concrete

Voids can affect the mechanical properties of PC and a high number of them is not

desirable. Reducing the voids population can enhance the mechanical properties

of the concrete (Knab et al., 1983) as the microstructure and location of voids have

a negative effect on mechanical strength. They can also influence the cracks that

emanate and propagate, resulting in failure of the composite material (Zhu et al.,

2011). In order to reduce the number of voids, a vibration table was used to induce

a high level of compaction for PC. There is a range of frequencies available on a

vibration table that used for achieving high level of aggregates compaction in PC.

Each frequency induces a specific level of compaction on a PC sample which has a

direct influence on mechanical properties. To find the optimum frequency, PC

samples were prepared using various frequencies during the compaction stage

and were tested for compressive strength. The PC sample with the highest

compressive strength is the one with the lowest voids population and the

optimum compaction.

173

Three accelerometers were mounted on the vibration table to capture the

frequency and the amplitude in three directions of X, Y and Z. Frequency was

measured in the same way as measuring the structural damping ratio described in

section 3.6.4. The only difference is that the calculation of the damping ratio is not

required. Frequency and amplitude are the main aims of this experiment. Figure

6.1 illustrates the experiment set up to measure frequency and amplitude of the

vibration table.

Figure 6.1 Experimental setup for measuring the frequency and the amplitude of a vibrating table.

174

The frequency controller of a vibration table starts at 0 Hz and finishes with 50 Hz.

The measuring of the frequency and amplitudes starts at 0 and goes up to 32 Hz.

When 32 Hz is reached, the accelerometer magnetic attachment will not remain

attached to the vibration table and falls down. Table 6.1 shows the result

measurement of frequency and the amplitude of the vibrating table. The results of

the measurements indicated that real frequencies are very close to the set values

indicated by the vibrating table. The direction of oscillation does not seem to have

an effect on the value of frequencies, as shown in Figure 6.2.

Table 6.1 The frequency and amplitude of the vibrating table.

Vibrating table

control reading

Frequency in X

direction, Hz

Amplitude in X

direction, mm

Frequency in Y

direction, Hz

Amplitude in Y

direction, mm

Frequency in Z

direction, Hz

Amplitude in Z

direction, mm

10 10 0.256 10 0.11 10 0.02

12 12 0.45 12 0.263 12 0.047

14 14 0.66 14 0.672 14 0.08

16 15.875 0.188 15.88 1.767 15.875 0.147

18 17.062 1.21 17.06 7.5 17.062 1.067

20 18.9375 2.7169 18.94 9.8 18.9375 2.162

22 21.375 3.097 21.38 8.888 21.375 2.5

24 23.5 2.24 23.5 8.9 23.5 2.814

26 25.56 1.66 25.56 8.5 25.56 3.66

28 27.5 2.7 27.5 8.71 27.5 5.4637

30 29.312 1.0189 29.31 8.06 29.312 5.8

32 30.375 0.766 30.38 7.499 30.375 13.853

175

As the frequency increases, the amplitude increases, particularly in Z direction for

frequencies more than 30 Hz, as shown in Figure 6.2.

0

2

4

6

8

10

12

10 15 20 25 30 35

Ampl

itude

(mm

)

Frequancy (Hz)

Frequancy in X direction

Frequancy in Y direction

Frequancy in Z direction

Figure 6.2 Relation between the amplitude and set frequency for the vibration table.

Different frequencies were applied during the packing operation of the PC

samples using the vibration table. The mould containing the PC sample was fixed

on to the vibration table and vibration applied to the PC sample as shown in

Figure 6.3. When the liquid resin reached the surface of the PC sample in the

cylindrical mould and the bubbles stopped coming out of the surface resin, the

vibration table was stopped.

176

Figure 6.3 The mould contains the PC sample mounted on vibration table, the frequency applied.

The PC sample was then left for 28 days to cure at the ambient temperature. Upon

completion of curing, the compressive strength was tested for each PC sample

according to Australian standard AS 1002.9 – 1986 “Method of testing concrete:

Part 9, Method for determination of the compressive strength of a concrete

specimen”. The method of testing is described in 3.6.2. The optimum frequency for

vibration and for producing a PC sample with the highest compressive strength

was found to be 18.9375 Hz (20 Hz by the vibration table switch controller), which

resulted in 109 MPa compressive strength for basalt, sand and chalk composition,

as shown in Table 6.2.

177

Table 6.2 Vibrating time and compressive strength of PC samples

Set frequencies on vibration table controller, Hz

Vibration time (min)

Frequency

Measured, X direction (Hz)

Compressive strength

(MPa)

16 10 15.875 98

18 12 17.062 93.5

20 16 18.9375 109

22 15 21.375 106

24 22 23.5 97

26 20 25.56 81

6.3 Identification of maximum moulding duration as a function

of moulding temperature and DMA content in resin binder

Moulding time is the time required to mix PC with aggregates, then pour the PC

mixture into the mould and vibrate the mould using a vibration table until the

vibration process finished. The Dimethyl aniline DMA (promoter) amounts,

MEKP initiator, monomer reactivity ratio and moulding temperature are the key

controls of resin rheological behaviour from the commencement of mixing

aggregates with the resin to the end of the final operation in vibrating the mould

(Ganglani et al., 2002, Yang and Suspene, 1991). In addition the DMA (promoter)

amount affects the mechanical and rheological properties of the resin (Ganglani et

al., 2002, Yang and Suspene, 1991) and hence has an effect on the PC composite’s

mechanical properties. During the moulding time the resin is required to be in a

liquid state. This enhances the wetting of the aggregate particles, improves the

mixing operation and increases particle settlement to achieve good mixing and

compaction. As a result there is a reduction in the number of voids. The overall

178

result is the enhancement of the mechanical properties of PC. To achieve such a

result, it is important to identify the DMA amount required correlate with the

moulding temperature, and the moulding time. Extending the moulding time up

to gel stage could cause some damage such as crack initiation during the

compaction process ,or result in a low level of mixing, both leading to reduced

mechanical properties of PC.

6.3.1 Effect of DMA (promoter) contents on temperature rise during curing

The effect of the DMA content on temperature rise during curing was

investigated. DMA content exerts an influence on the temperature of resins during

their curing. Resins without DMA did not exhibit any recordable rise of

temperature while resins with DMA had temperature increases up to 120 °C for

0.3% of accelerator. The increase of DMA content leads to an increase in the

exothermic maximum resin temperature during the curing and shortens the time

needed for a temperature rise, as shown in Table 6.4. The method of measuring

temperature was described in Section 3.4.2.2.

179

-20

0

20

40

60

80

100

120

140

0 100 200 300 400 500 600

Tem

pera

ture

(°C)

Time (min)

0% DMA

0.1% DMA

0.2% DMA

0.3% DMA

Figure 6.4 Temperature of MMA/ARAPOL resins with different content of DMA.

6.3.2 Effect of DMA contents on viscosity growth during resin

copolymerization

The effect of DMA on the curing rate was investigated by increasing the initial

content of 0.001 in 40% ARAPOL/60% MMA resin composition and adding more

DMA to the mixture. The addition of DMA increases the initial viscosity of the

mixture in the curing process. The amount of DMA was varied from 0.001 to 0.003,

causing an increase of the viscosity growth rate, as shown in Figure 6.5. The

method used to measure viscosity was described in Section 3.4.2.3.

180

0

100

200

300

400

500

600

700

0 20 40 60 80 100 120 140 160

Visc

osity

(cP)

Time (min)

DMA 0%

DMA 0.1%

DMA 0.2%

DMA 0.3%

Figure 6.5 Viscosity of resins versus their curing time for a variety of DMA content.

Varying the DMA content is another measure that is used to demonstrate the

effect of DMA content on the time required for the resin to reach the maximum

viscosity as shown in Figure 6.5. An increase in the DMA content and the

moulding temperature decrease the time required for the resin maximum viscosity

to be reached, as shown in Figure 6.6.

181

0

50

100

150

200

250

300

350

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35

Tim

e whe

n th

e max

imum

visc

osity

(6

40cP

) rea

ched

(min

)

DMA content (%)

Temperature 25°C

Temperature 20°C

Temperature 15°C

Temperature 10°C

Figure 6.6 Time to the maximum temperature of 40% ARAPOL/60% MMA resins with different contents of DMA for various moulding temperatures.

The time required for the resin to reach maximum viscosity is essential knowledge

when manufacturing bases for precision tool machinery. The reason is both the PC

mixing and the moulding tasks should be accomplished prior to maximum

viscosity being reached by the resin binder (640 cP), which is on the verge of the

gel point. A drastic increase in viscosity hinders mixing, resulting in PC material

not to be mixed and moulded efficiently. The effect of both temperature and DMA

amount will be combined in a convergence on the PC base’s mechanical properties

and curing behaviour. The relation between time of viscosity build-up t (min),

temperature T (°C) and DMA content C (%) can be described in the following

empirical equation:

182

)1.6...(..............................069.01.542.6 TCnt −−=l

Using the above equation, the DMA amount was calculated which is compatible

with the known moulding temperature, as illustrated in Table 6.3.

Table 6.3 Recommended DMA content for different moulding temperatures.

T(°C) 8 9 10 11 12 13 14 15 16 17 18

DMA (%) 0.3 0.29 0.27 0.26 0.25 0.23 0.22 0.21 0.19 0.18 0.17

T(°C) 20 21 22 23 24 25 26 27 28 29 30

DMA (%) 0.14 0.13 0.11 0.10 0.09 0.07 0.06 0.04 0.03 0.02 0.0

By using Figure 6.6, the recommended DMA content for the various moulding

temperatures in Table 3.3 can be validated. For example, the recommended DMA

for 10 °C moulding temperature is 0.27 %. In Figure 6.6 the time required to reach

the maximum measurable viscosity (640 cP) is 73 minutes at 10 °C and 0.3 %

DMA. When DMA is reduced, the time for reaching the maximum viscosity

increases at a particular temperature. This indicates that the time for reaching the

maximum viscosity is greater than 73 minutes when the DMA amount is less than

0.3% at 10°C, the time considered when the DAM amount calculated for Table 6.3

is 75 minutes approximately. The required time for moulding is 40-50 minutes,

depending on the size of the PC base and the complexity of the design. The

recommended DAM correlated with temperature in Table 6.3 provides 15-35%

extra time to the required time as an extra precaution to guarantee that the

moulding operation takes place when the resin is at the low viscosity level. This is

to avoid reaching the verge of gel time, especially during compaction stage that

183

may initiate undesirable micro-cracks in the polymeric matrix that can propagate

during the solidification of the base, since UPE resin has high shrinkage compared

to epoxy.

6.3.3 Effect of DMA content on curing behaviour of resin binder

The effect of DMA on curing behaviour was investigated using Differential

Scanning Calorimetry (DSC) and the Borchardt and Daniels equation (Borchardt

and Daniels, 1957). Their kinetic approach facilitates the evaluation of activation

energy (Ea), the pre-exponential factor (Z), heat reaction (ΔH), reaction order (n)

and rate constant (K) from a single scanning. The results of the DSC tests

demonstrate the difference between samples with and without DMA, as shown in

Figure 6.7. Thus, the presence of DMA could shift the peak of the DSC curves to

higher temperatures resulting in a stronger exothermal reaction, as the area under

the DSC curve is bigger in the case of the sample with 0.3% DMA. The presence of

DMA, as expected, changes the parameters of the Borchardt and Daniels model.

However, the variation is not too high as can be seen in Table 6.6. The method of

conducting the DSC analysis was described in section 3.4.2.4.

184

Table 6.4 Parameters of Borchardt and Daniels model for 40%ARAPOL /60%MMA resins with different contents of DMA.

DMA content,%

Reaction order, n

Activation energy, kJ/mol

Log Z, log(1/min)

Heat of Reaction

0 2. 95 204 30.4 84

0.1 2.84 203 30.1 98

0.2 2.74 193 28.9 100

0.3 2.65 195 29.5 101

Figure 6.7 DSC curves of 40%. ARAPOL/60%MMA resins without DMA (solid curve) and with 0.3% of DMA (broken curve).

The heat of reaction is increased as DMA (promoter) amount is increased as

shown in Table 6.4. This result supported the outcome of the exothermal

185

temperature profile as shown in Figure 6.4, the peak exothermic temperature

increase as DMA amount is increased.

6.3.4 Effect of DMA contents on resin binder mechanical properties

The effect of DMA on the resin’s mechanical properties was investigated using

flexural strength, tensile strength and elongation. The method of measuring

flexural strength and tensile strength testing was described in Sections 3.4.1 and

3.4.1.2. Tensile strength, flexural strength and elongation all decreased with an

increase in DMA content, as illustrated in Table 6.5. Thus the strength of resins

with 0.3% DMA is 25% lower than resins without DMA. Elongation is also

reduced by 18% and these results are in partial agreement with those of Ganglani

et al. (Ganglani et al., 2002). This is attributed to the formation of micro-cracks,

possibly caused by the excessive exothermal reaction in the presence of the

accelerator as the exothermic reaction peak temperature increased as DMA

amounts increase as shown in Figure 6.4. This caused non-uniform temperature

distribution across the resin sample and initiated non-uniform shrinkage when the

resin solidified. It should be noted that this effect may be much greater with larger

volumes of resin, because of the scale factor. Taking into account the very low

fraction of resin (the micro-layer thickness between aggregates) in PC composite

material and the substantial heat exchange between the matrix and the fillers, the

detrimental effect of DMA on mechanical properties ought to be much lower.

186

Table 6.5 Mechanical properties of resins with different volume fractions of DMA.

DMA content, %. 0 0.1 0.2 0.3

Modulus of elasticity (MPa) 705 759 798 675

Tensile strength (MPa) 60.2 58.6 51.9 43.6

Elongation (%) 10.1 9.3 8.1 8.3

Flexural strength (MPa) 130 128.2 119.3 109.5

6.4 Optimization of mixing technology of PC

The main purpose of concrete mixing is to achieve a uniform mixing of all

materials (ACI, 1972). Mixing technology is an important parameter for a PC with

low binder content. Poorly mixed PC not only fails to meet the requirements for

workability but also affects the PC’s mechanical properties. Three mixing

technologies were investigated for a specific aggregate composition (basalt, sand,

flay ash).

The first mixing technology (MT1) started by mixing the fine aggregate with 75%

of the resin, followed by the medium-sized aggregate and then, finally, the coarse

aggregate was added to the main mixture with the rest of the resin. The second

mixing technology (MT2) began by mixing 20% of the resin with coarse aggregate.

The micro-filler was separately mixed with 30% of resin and then added to the

coarse aggregate resin mixture. The rest of the resin was separately mixed with the

medium-sized aggregate and then mixed with the main mixture. In the third

mixing technology (MT3), all aggregates were premixed and then mixed with the

187

resin. A traditional concrete mixer was used to mix the PC for all the mixing

technologies. A time of 15 minutes was used for all three mixing technologies.

Samples to measure flexural strength were prepared for each mixing technology.

A four-point flexural strength test was conducted according to the Australian

standard AS 1012.11-2000 method of testing concrete. The method used to test

flexural strength was described in Section 3.6.3. Table 6.6 shows the flexural

strength for all mixing methods. MT1 proved to be the most effective for basalt,

sand and fly ash, and flexural strength reached the maximum of 22.6 MPa.

Table 6.6 Effect of mixing technology on flexural strength of PC.

Mixing technology Composition Flextural Strength (MPa)

MT1 Basalt ,sand , fly ash 22.53

MT2 Basalt ,sand , fly ash 19.23

MT3 Basalt ,sand , fly ash 20.32

188

6.5 Conclusions

This chapter has examined aspects of moulding technology. Each has a different

effect and influences the mechanical properties and curing behaviour of PC by

various means. The optimum frequency when operating the vibration table to

prepare a PC sample is identified as 18.9375 Hz. With this frequency, the PC

samples produced the highest compressive strength. An empirical relationship

connecting the moulding temperature and the DMA content was obtained using

rheological analysis of the resin with various amount of DMA. A table showing

moulding temperatures in the range of 8-30°C with DMA amounts in the range of

0-0.3% was constructed. It was found that increasing the DMA fraction in the resin

binder has a slightly negative impact on the mechanical properties and increases

the curing rate as well as the exothermic temperature profile. Various mixing

technologies were investigated in order to obtain one that produces the PC with

the highest flexural strength. It was found that MT1 produces a PC sample with

22.53 MPa, which is the maximum flexural strength.

189

Chapter 7

7 Influence of moisture on the thermal and

mechanical properties and curing behaviour of

a polymeric matrix and PC composite system

7.1 Introduction

Moisture is mainly free water found in voids and capillary pores in the filler

aggregate (Lamond and Pielert, 2006). Water also can be found as ingress moisture

in the carbon fibres used in PCs containing fibre-reinforced polymer (Tuakta and

Buyukozturk, 2011). All forms of moisture are dependent on the humidity level of

the local conditions and the micro-climate of the material. This subject is covered

in the research literature with the primary focus on (i) the moisture sorption of the

resin binder after the curing is completed and the PC composite is implemented in

a specific application, for example in underwater constructions (Y.Ohama, 1997)

and (ii) the pre-existing water in aggregates, where 3% of pre-existing water in

aggregates has been found to reduce the compressive strength of PC by a half

(Fontana and Reams, 1985). It was also reported that PC consisting of unsaturated

polyester, styrene and acid monomers, such as maleic anhydride, are successfully

190

polymerized in the presence of 5% water with improved mechanical properties

compared to the same PC without maleic anhydride containing the same level of

moisture (Ignacio et al., 2008).

Ignacio et al. (2008) state that water molecules trapped inside ionic cages interfere

less with the overall curing process for UPR (Ignacio et al., 2008). The remain of

other effects of pre-existing water in aggregates on PC’s mechanical and thermal

properties and curing behaviour for both PC and resin binder that have not

received adequate attention to date. In this chapter the influence of moisture on

the thermal and mechanical properties, and the curing behaviour of a polymeric

matrix and PC composite system are investigated.

7.2 Sample preparation

Sample preparation for the resin domain and the PC composite is reported in the

following sections.

7.2.1 Resin domain

The resin investigated was made from commercial general purpose, unsaturated

polyester (AROPOL) (67% unsaturated polyester dissolved in 33% styrene) and

obtained from Huntsman Chemical Company (Australia). Methyl methacrylate

(MMA) was obtained from Degussa (Australia), cobalt octoate and dimethyl

aniline (DMA) from Alfa Aesar (USA), and methyl ethyl kenton peroxide (MEKP),

commercially known as NR20, from Nuplex Industries (Australia). A resin sample

was produced by mixing 3:2 (v/v) UPE/MMA. 0.8% cobalt octoate (promoter),

0.2% DMA (accelerator) and 2% (v/v) MEKP (initiator) were then added to this

191

mixture, in this sequence by hand for 1-2 minutes. 1% - 5% (v/v) of water was

then added to the mixture to investigate the effect of the moisture content on the

curing process and the final polymeric matrix properties.

7.2.2 Polymer concrete composite

The basalt and sand used as filler aggregates were from Roca, and the fly ash was

supplied by Cement Independent Australia. The PC mixture contained fine

aggregate 8.3%, coarse aggregate 49.8% and medium-sized aggregate 24.9% (v/v).

Aggregates were heated using a vacuum chamber to produce zero moisture

aggregates. When the zero moisture aggregates were produced, a moisture check

was conducted using moisture analyzer MD 150 from Starous, Germany, thus

ensuring that the level of moisture was zero. 1% - 5% (v/v) of water was then

sprayed on to each aggregate individually. Each aggregate was left for 30 minutes

with the mixer on to evenly distribute the water. Samples of aggregates were

checked for moisture levels using the same moisture analyzer. When the mixing of

water and aggregates was accomplished, 17% (v/v) of resin was mixed with the

aggregates. The mixing was continued for 20 minutes to ensure the best mixing of

all particles with the resin, and in order to maximize the resin interface with the

pebbles. The mixture of resin-aggregate was poured into a rectangular mould

assembly (100 × 100 × 300 mm), which had been coated with a release agent

consisting of a gel coat and PVA to prevent adhesion to the steel mould. The PC

sample was cured for 28 days at ambient temperature. The flexural strength of the

PC samples was measured using a Snitech 60/D universal testing machine

according to Australian standard AS 1012.1, and the testing method is described in

Section 3.6.3. A German ALPHA 3, with two columns, was used to measure the

compression strength of the PC according to Australian standard

AS1012.19.2.2000, and the method of testing is described in Section 3.6.2. The PC

192

samples for compression were prepared following the same procedure as was

used for the flexural strength test. The mould used for the compression strength

PC sample was cylindrical, 100 mm in diameter and 300 mm in length. A sample

with the same measurements as those used for flexural strength testing was used

for measuring the CTE of the PC composite system, using the method described in

Section 3.6.5.

7.3 Results and discussion

A series of experiments was conducted to investigate the water–resin interaction

in the polymeric matrix domain and in a PC composite system. The thermal and

mechanical properties and the curing behaviour of UPE were computed and

analysed. The thermal and mechanical properties of the PC composite systems

were measured and explained. The moisture of the aggregates used for PC was

measured and then the solubility of the water in the components of the resins

studied was examined. MMA water solubility was 1.2%, as shown in Table 7.1. If

more than 1.2% water was added and mixed with MMA, the water appeared to be

undissolved in the MMA. When mixing stopped, the water droplets stayed at the

bottom of the beaker. ARAPOL (UPE dissolved with 33% styrene) was immiscible,

as water was emulsified when it was added and mixed with the resin. This

indicates that up to 60% of added water (1.2% MMA water solubility) will be

dissolved in the MMA when the percentage of water is 1%. The rest of the water

will mainly evaporate during the copolymerization process due to the heat

generated by the exothermic reaction. When 1% of water was added to the resin

composition, the share of MMA (1.2 ×60%) is 0.72 and the share of Dimethyl

aniline (DMA)(0.2%×80%) is 0.03. According to Table 7.1, those components are

the only soluble ones. The total ratio of soluble water is 0.75% in the resin. In

193

another words, the resin will reach saturation when the water added is 0.75% of

the resin volume.

Table 7.1 Water solubility for polymeric matrix contents.

Component Volume fraction in polymeric matrix

water Solubility

Arapol UPE ( dissolved in 33%

styrene)

40% Immiscible

Styrene Immiscible

Methyl methacrylate (MMA) 60% 1.2%

Dimethyl aniline (DMA) 0.2 % (80%) Highly soluble

Cobalt octoate 0.8% Immiscible

Methyl ethel kenton (MEKP) 2% 1%

7.3.1 Measuring the level of moisture in aggregate

The moisture test for the aggregate mixture, using a moisture analyser MD 150,

indicated that there was a variation in the level of moisture, depending on the

climate, and specifically on the local humidity. Figure 7.1 shows the level of

moisture in the aggregate during the days of the week.

194

1.6

0.94

1.24

0.83

1.051.1

1.8

0

1

2

0 1 2 3 4 5 6 7 8

Moi

stur

e co

nten

ts (%

)

Days of the week (day)

Figure 7.1 Moisture during the days of the week in aggregate used in polymer concrete.

7.3.2 Curing behaviour of the polymeric matrix

The effect of water on the resin curing process is assessed by DSC measurements.

The Borchardt and Daniels model was used to analyse the results and calculate the

reaction activation energy (Ea), pre-exponential or Arrhenius frequency factor (Z),

heat reaction (ΔH), reaction order (n) and rate constant (K) from a single scanning

for the various water contents (Borchardt and Daniels, 1957). Their approach states

that the curing reaction follows nth order kinetics and obeys the following

equation:

195

)1.7...(......................................................................]1)[( naTKdtda

−=

where dtda is the reaction rate, a is the fractional (reaction progress %), )(TK is the

specific rate constant at temperature and n is the reaction order. Borchardt and

Daniels assume Arrhenius behaviour:

)2.7........(............................................................)( /RTEaZeTK −=

where (Z) is the Arrehenius frequency factor (1/sec), (Ea) is the activation energy

(J/mol) and R is the gas constant 8.314 (J/mol °K). The DSC was conducted to

examine the effect of moisture on the polymeric matrix. The method is described

in Section 3.4.6. Utilizing a software feature supplied by TA Instruments (TA

Speciality Library), resulted in the parameters of the Borchardt and Daniels model

in Equations 7.1 and 7.2 being obtained, as shown in Figure 7.2.

196

Figure 7.2 DSC data processing using the TA Specialty library: inset time of 70% conversion at 60 °C versus water content.

The time of 70% conversion at 60 ℃ was estimated for various moisture contents,

and Figure 7.3 show that an increase in water content generates an elevation in

conversion time (time of reaction). An increase in water content leads to elevated

activation energy and a reduction in the heat of the reaction as the moisture

content rises. This illustrates the retardation effect of moisture during the curing,

as shown in Table 7.2.

197

0

10

20

30

40

50

60

70

80

0 1 2 3 4 5 6

Tim

e of

con

vers

ion

(Min

)

Water (%)

Figure 7.3 Time of 70% conversion at 60 ℃ versus water content.

When water is added, a small portion of the water dissolves in the monomer

(MMA), producing a mixture that is more stable and needs higher activation

energy to initiate the chemical reaction. As a result, the heat of the reaction is

reduced (see Table 7.2).

198

Table 7.2 Parameters of Borchardt and Daniels model for different resin moisture contents.

Moisture content %

Reaction order, n

Activation energy

[kJ/mol]

Log Z, log(1/min)

Heat of Reaction, [kJ/mol]

0 2.59 204 30.4 88.4

1 3.11 210 31.1 84.0

3 3.20 245 36.0 78.8

5 3.70 287 42.9 64.1

An increase in viscosity in the course of curing as the amount of moisture

increased was supported by the DSC outcomes. Figure 7.4 shows that an increase

in water content delays the increase in viscosity and increases the gel time. An

increase in moisture content slows down the cross-linking process

(copolymerization). Figure 7.4 inset shows that a greater time is needed to reach

the gel stage as the moisture increase. A possible explanation for this outcome is

that the energy generated by the exothermal reaction during the curing is

consumed by the evaporation of water droplets, leaving less energy for the

process of copolymerization. As a result, a lower curing rate is observed as the

moisture content increases. The method of measuring viscosity was described in

Section 3.4.2.1 and the method of measuring gel time was described in Section

3.4.2.3.

199

0

100

200

300

400

500

600

700

0 50 100 150 200 250

Visc

osity

(cP)

Curing time (min)

Water 0% Water 1%Water 3%Water 5%

50

90

130

170

210

250

0 2 4 6

Gel

Tim

e (m

in)

Water (%)

Figure 7.4 Viscosity increase for UPE containing various amounts of water: inset gel time versus water percentage in UPE.

7.3.3 Interaction of polymeric matrix with water

FTIR spectroscopy demonstrated the interaction between water and UPE

functional groups. Figure7.5(A) illustrates a peak between 3240 – 3270 cm-1. The

C=O stretching is observed as a peak at 1717 cm-1 in unsaturated polyester resin

(UPE) prepared with no initial water. The peak develops a shoulder at 1736 cm-1

with increasing water content. This is due to the formation of a different C=O

bond strength between the water and carbonyl group in UPE, as illustrated in

Figure7.5(B). Hydrogen bonding can form between water and the oxygen in C-O

in both ether and ester functional groups. This increases the peak width and

intensity at 1142 and 1460 cm-1, as shown in Figure7.5(C). This chemical interaction

of water and UPE may be another factor in the weakening of the mechanical

properties. The method of conducting FTIR spectroscopy was described in Section

3.4.2.7.

200

90

91

92

93

94

95

96

97

98

99

100

260031003600

T%

υ (cm-1)

0%v water

1%v

2%v

4%v

5%v

60

65

70

75

80

85

90

95

100

1650170017501800υ (cm-1)

60

65

70

75

80

85

90

95

100

850105012501450υ (cm-1)

(A) (C)(B)

Figure7.5 FTIR spectra of polymeric matrix prepared with 0, 1, 2, 4 and 5%v initial water, (A) O-H and C-H stretching peaks, (B) C=O stretching peak and (C) the range including C-O and C-H bending.

7.3.4 Thermal Gravimetric Analysis (TGA)

TGA analysis of the polymeric matrixes containing various amounts of water was

conducted, using the method of testing described in Section 3.4.2.6. Figure 7.6

shows a peak below 250°C, a peak around 385 °C and two shoulders around 410

and 450°C. The initial weight loss can be assigned to the residual bound water

from the resin. This process shows a peak in the derivative of weight loss (dw/dT)

form of the data as shown in Figure 7.6. This peak shows a shift from 226 °C for

the sample containing 1% initial moisture to 203, 181 and 168 °C for the 2, 3 and

5% initial moisture levels (Figure 7.6 inset). This shift may be due to two reasons:

(i) the rate of weight loss depends on the mass transfer during the heating process,

and this mass transfer depends on the water molecule diffusion through the pores

in the resin. Higher initial moisture leaves a higher pore volume ratio and

therefore causes the shift of the weight loss peak of the bound water to lower

201

temperatures. (ii) When a higher initial moisture level exists in the resin mixture,

the water molecules have higher probability to participate in the curing process

which is evidenced in the overlap of peaks at 385 and 450 °C in the resin

decomposition region. Water may hydrolyse ester groups in UPE, especially at the

high temperatures of the curing process, or terminate an active radical causing a

less cross-linked network. The temperature of bound water evaporation exhibits

the strength of interaction between water molecules and functional groups in the

polymer network. Most water at lower ratio is completely soluble in the starting

composition mixture, causing the imprinting of water molecules in the network.

Figure 7.6 TGA of polymeric matrix containing various amounts of water. The inset show an expended region of water evaporation weight loss (the graphs are scaled up by 1% for clarity).

202

Table 7.3 Peak temperatures for resins containing various amounts of water

Temperature Moisture

226°C 1%

203°C 2%

181°C 3%

168°C 5%

7.3.5 Resin domain mechanical properties

The effect of water content on the mechanical properties of the UPE resin was also

examined. All methods used for the mechanical testing of the polymeric matrix

were described in Section 3.4.1. The modulus of elasticity, Shore D hardness,

flexural strength and tensile strength all deteriorate as water content increase, as

illustrated in Figure 7.7.

203

Figure 7.8 Mechanical properties of UP/S/MMA polymeric matrix as a function of water percentage; (A) Modulus of elasticity, (B) Tensile strength versus, (C) Flexural strength versus water percentage, (D) Tensile strength.

This may be due to the pores left by water droplets or water vapour bubbles

generated during the exothermic curing process, as seen in the SEM images in

Figure 7.9, where pores act as stress concentration weak points in the resin

structure and result in resin failure during loading tests. This is consistent with the

work of Athijayamai et al (Athijayamani et al., 2009).

204

Figure 7.9 SEM images for flexural fracture resin containing different amounts of moisture; (A) moisture 1%, (B) moisture 3%, (C ) moisture 5%. Scale bar is 10 µm for all images.

In the early stages of the reaction, water is distributed in droplet shapes because it

is mixed with the resin domain. These water droplets prevent the active ends of

the macromolecules forming a cross-linked network and, to some extent, prevent

further copolymerization. The temperature builds up in the resin binder due to the

exothermal reaction of UPE resin. The generated energy during the exothermic

reaction is the main source of the chemical energy used to drive the

polymerization process only when the moisture is 0%. A portion of the main

chemical energy is taken to be used in evaporate the water in the course of curing.

This leads to the formation of pores (voids) that affect the mechanical properties of

the resins and delay curing. The evaporation of the water droplets creates voids

with a spherical shape. Scanning electron microscopy was utilized to examine the

microstructure of the fractured surface of the resins. Figure 7.10 exhibits a flexural

test fracture surface, showing the hemispherical voids contain an active cross-

linked network, ending at the edge of the half sphere. This interface forms a phase

separation with a rough surface on the internal surface of the sphere.

205

Figure 7.10 Half sphere void exhibiting the nature of a void inner surface for polymeric matrix fracture (scale bar is 1 µm).

Figure 7.11 shows the voids formation during the early stages of curing the resin

binder in liquid sate.

Figure 7.11 Voids forming due to water existence at the early stage of curing resin containing 5% moisture.

206

The ratio of void volume to sample volume in resin (abbreviated as VV/SV) was

calculated for each sample, using image-processing technology facilitated by

Image J 1.42q software, and assuming that the polymeric matrix was uniform and

that all voids were cylindrical. The cylindrical geometry goes along the material

volume to accommodate all voids that exist in the material volume. The VV/SV

was approximately three times greater than the actual moisture content in each

sample. This is an indication of the effect of water droplet evaporation when the

resin is at the gel stage. The vapour pressure was sufficient to significantly expand

the volume of voids to double that prior to solidification. This phenomenal

inflation has a deleterious impact on the mechanical strength of the resin domain,

and explains why the mechanical strength drops so dramatically.

7.3.6 Dynamic Mechanical Analyses (DMA)

Measurement of the dynamic properties of the resin domain is essential when

considering its usage as a binder in applications such as in PC in the production of

a base for precision tool machine. Due to its damping properties, DMA testing was

conducted to measure the damping factor (tan δ) and storage modulus. The

method was described in Section 3.4.1.4. Figure 7.12(A) shows that the storage

modulus declined for the resin as the water content increases. This behaviour can

be explained by a dramatic change in morphology and by an increase in micro-

cracks and voids as the water content increases. Figure 7.12(B) shows that the

damping factor (tan δ) increases as the water content increases. The increase in

micro-cracks and voids as the moisture content increases may also explain the

increase in the tan δ (Panteliou and Dimarogonas, 2000). Micro-cracks and

porosity are good dampers due to the inner friction inside a crack, which increases

the damping properties.

207

Figure 7.12 DMA analyses (A) storage modulus of polymeric matrix versus frequency (B) tan δ versus frequency for different water percentage.

7.3.7 Coefficient of thermal expansion (CTE) of polymeric matrix

The other important factor in applying UPE resin as a binder in PC for bases of

high precision machines is its CTE. The CTE was measured for various resins

containing different amounts of water. The method was described in Section

3.4.2.3. Figure 7.13 show that the increase in moisture content caused an increase

in the CTE of the polymeric matrix. An increase in the number of voids results in a

decrease in the resin density and modulus of elasticity as well as other mechanical

properties, as demonstrated earlier. This leads to a reduction in the resistance of

the material to the thermal expansion. Another parameter, the thermal

conductivity of the polymeric matrix, also decreases as a result of the increase in

the number of voids, which are full of air and reduce the heat dissipation inside

the polymeric matrix. All of these occurrences converge to increase the CTE of the

polymeric matrix as the water content increases.

208

75.0

100.0

125.0

0 1 2 3 4 5 6

CTE ×

10-6

(°C-1 )

Water (%)

Figure 7.13 Coefficient of thermal expansion (CTE) of polymeric matrix verses water percentage.

7.4 Mechanical properties of polymer concrete composite

material

Mechanical properties were measured for the PC, including flexure strength and

compressive strength. The flexural strength test was conducted according to the

AS 1012.11-2000 method of testing concrete described in Section 3.6.3. The flexural

strength decreases catastrophically, with a loss of 99% of its initial value as the

water content reaches 5%, as shown in Figure 7.14.

209

22.373820.8775

4.24546

1.776809 0.97689 0.81687 0.67810

5

10

15

20

25

0 1 2 3 4 5 6

Flex

ural

stre

ngth

(MPa

)

Moisture contents (%)

Figure 7.14 Flexural strength of polymer concrete composite system versus the percentage of moisture contents.

The BET surface area analysis was conducted for all aggregates using the method

described in Section 3.3.5. Table 7.4 shows that the BET analysis indicates that

extremely low microspores were detected for the aggregate in this study. Thus the

added water to these aggregates is mainly present on the highly hydrophilic

surface of these filler particles, affecting the strength of the bond with the resin.

210

Table 7.4 BET analysis of all aggregates used in the composition of polymer concrete

A rather large proportion of the moisture in coarse aggregates is located at the

surface of the aggregate. The thin micro-layer of the moisture affects the interfacial

adhesion bonding between the aggregate and the polymeric matrix, as shown in

Figure 7.15. An increase in the moisture content in the polymer concrete composite

system increases the debonding of aggregates with the polymeric matrix and

decreases the polymeric matrix strength when the moisture droplets are

suspended in the middle of the interfacial bonding, as shown in Figure 7.15 those

droplets become voids and delay the curing process of PC. This is the cause of the

reduction in flexural strength, with an increase in the moisture content in the PC

composite system. Figure 7.16 shows a PC sample containing 5% moisture, and

there appear to be many debonding points between aggregate and resin.

Fly Ash Sand Gravel Spodumene Basalt Chalk

BET surface area (m2/g): 1.01990 0.28880 0.12630 0.10640 0.21800 1.60810

Langmuir surface area (m2/g): 1.16590 0.33430 0.14740 0.12380 0.25120 1.84920

Microspore area (m2/g): -0.4023 -0.2320 -0.1134 -0.12710 -0.1481 -0.823

External Surface area (m2/g): 1.42230 0.52090 0.23960 0.23340 0.36610 2.43150

Microspore volume (cm3/g): -0.00014 -0.00009 -0.00004 -0.00005 -0.00006 -0.0003

211

Figure 7.15 Water distributions on a polymeric matrix and the interfacial bonding of matrix – aggregates in a polymer concrete composite system.

Figure 7.16 PC sample containing 5% moisture.

212

Compressive strength was measured according to the AS 1002.9 1986 method

described in Section 3.6.2. The compressive strength decreases as the moisture

increases, as shown in Figure 7.17 as the water percentage reaches 5%, the

compressive strength diminishes by 55% of the initial value when the water

percentage was zero.

50

100

150

200

0.0 1.0 2.0 3.0 4.0 5.0

Cmpr

essiv

e stre

ngth

( MPa

)

Water (%)

Figure 7.17 Compressive strength of polymer concrete composite system verses the percentage of water content.

Based on Figure 7.18 and Figure 7.14, at the point when the moisture is 0.002%

there is a very small decrease in compressive and flexure strength but this is

negligible. It is, therefore, reasonable to suggest that when the moisture content is

0.002% or below, the overall aggregate composition is acceptable.

7.4.1 Coefficient of thermal expansion (CTE) of PC composite system

The CTE was measured in different samples of PC containing a variety of

moisture contents using the method described in Section 3.6.5. The main

213

parameters influencing the CTE of the composite material are the volume fraction

of both the fillers and the matrix. The CTE values for fillers and matrix, as well as

the strength of the interfacial adhesion between the polymeric matrix and filler

aggregate all affect the CTE of PC composite. The moisture can be located on the

surface of the aggregates or emulsified in the polymeric matrix as a result of the

mixing process, as shown in Figure 7.15. During the curing of a PC composite, the

matrix is surrounded by aggregates that have low thermal conductivity

(Demirboga and Gul, 2003), which results in intensifying most of the heat

generated by the resin exothermic reaction contained within the resin domain

itself. This results in the formation of more voids than when the resin domain

interacts with moisture without aggregates. The strength of the PC composite

system decreased due to the presence of the moisture. Decreasing the strength of a

polymer concrete composite system will reduce the material resistance for thermal

expansion caused by the temperature increase. This may explain why the CTE of

the PC composite system increases as the water content increases, as illustrated in

Figure 7.19. Based on Figure 7.1, at the point when the moisture is 0.002% there is

a very small increase in CTE that can be ignored. When the moisture is 0.002% or

below in the overall aggregate composition, since the change in CTE is very low. It

is, therefore, reasonable to say that this is acceptable.

214

10.0

15.0

20.0

25.0

0 2 4 6

CTE

×10-6

(°C-1

)

Water (%)

Figure 7.19 CTE of the PC composite system versus water content

7.5 Conclusions

The curing behaviour of a polymeric matrix is substantially affected by moisture.

Increasing the moisture causes an increase in the curing time and hence reduces

the curing rate. Evaporation of the moisture also consumes the energy intake

generated by the exothermic reaction originally required to cure the polymeric

matrix. This results in a serious delay in the curing of the polymeric matrix. The

thermal and mechanical properties are affected substantially by moisture in both

the polymeric matrix and the PC composite system. The effect of moisture on the

mechanical properties of the resin domain (flexural strength, tensile strength,

modulus of elasticity and hardness) is large, and appears in flying colours in as

shown in Figure 7.8. An increase in moisture decreases the mechanical strength of

the resin domain due to the morphology change caused by the rapid increase in

the void population and micro-cracks. The chemical energy generated by the

215

exothermic reaction and the moisture causes the inflation of voids at the gelation

stage during the curing of the resin domain. This results in a doubling between the

aggregates and the matrix of and an increase in the volume of voids to twice. The

DMA results emphasize the increase in the damping factor with an increase in the

water content of the resin domain. Increasing the damping factor is desirable for a

specific application, such as PC for a precision machine. However, in view of the

other unfavourable effects caused by water on the resin domain and the PC

composite system, the elevated damping factor was ignored. The CTE of the

polymeric matrix increases as the water content increases. The influence of

moisture on the main mechanical properties of the PC composite system reveals

that an increase in moisture would lead to a decrease in both the flexural and

compressive strength at different rates. The flexural strength of the PC composite

system loses 99% of its initial strength when the moisture content is 5%. The

compressive strength loses 65% of its initial strength when the moisture content is

5%. The CTE of the PC composite strength decrease up to 50% as moisture content

reaches 5%. FTIR spectroscopy scans show an interaction between water and the

functional groups of the resins. TGA analysis enables the classification of water in

resin binder based on the strength of the interaction between water molecules and

functional groups in the polymer network. Increasing the water content increases

the level of non-interactive water (bulk water) since the resin reaches saturation

when the water content is 0.716 approximately. The existence of water in the

particulate fillers can have a negative effect on both the productivity of a PC

structure and the end-use mechanical properties. Drying of aggregate fillers

affected by moisture should be an essential procedure in raw material preparation

for PC. The allowable moisture must be as close to zero as possible. 0.002% may be

an acceptable level of moisture in the aggregates used in manufacturing PC

composite material.

216

Chapter 8

8 Maturity studies of polymer concrete

8.1 Introduction

The maturity method is a technique that accounts for the combined effects of time

and temperature on the strength development of concrete (Carino and Lew, 2001).

The concept of the maturity method is often used for cement concrete strength

prediction. Both cement concrete and PC are composite materials, their main

difference being the chemical nature of their mortar. PC mortar is a thermosetting

binder, whereas the mortar of ordinary concrete is a cement paster. By definition,

the maturity aspect for PC is therefore similar to ordinary concrete in some

respects. Two common parameters, temperature and time, have the same effects

on both PC and ordinary concrete in different forms and levels. The parameters

driving the maturity operations of PC are directly connected to the curing of the

thermosetting binder resin, which depends on the initiator, accelerator (Yang and

Suspene, 1991), temperature of curing (Zheng et al., 1988) and monomeric

reactivity ratio (Sanchez et al., 2000, Rodriguez, 1993). The curing of cement

concrete depends on the temperature and chemical content of the cement paster

(Carino and Lew, 2001). In addition, while watering enhances the strength

development of cement concrete (Powers, 1948), the existence of water in the

217

aggregates in PC reduces the mechanical strength rapidly (Fontana and Reams,

1985). The common parameters for deriving the maturity of both PC and cement

concrete are the maturing temperature and time. These parameters were used as

the main drivers for the nominated maturity method. The maturing of the PC base

takes a month or sometimes more when matured under the ambient temperature.

This time is considered a long lead-time, and requires considerable storage space

for thee tons of bases. Increasing the productivity and decreasing the lead-time

would have a major impact on the cost of the PC base, and enhancing the maturity

would have a positive effect on both productivity and the quality of PC base. In

this chapter, the maturity method is identified. PC samples were heated for

various periods of time at different temperatures, according to the maturity

method. PC samples with different maturity conditions were tested for flexural

strength. The datum temperature was calculated and a mathematical expression

was obtained to predict the correlation of the relative flexural strength with

maturity temperature.

8.2 Maturity method

The demand for a procedure accounting for the combined effects of time and

temperature on strength development for different elevated temperatures grew as

concrete material evolved. It had been proposed that the product of time and

temperature could be used for this purpose for ordinary concrete (McIntosh, 1949,

Nurse, 1949, Saul, 1951). These approaches led to the construction of a

relationship, known as the Nurse-Saul maturity function:

)1.8(..................................................))(())(,(0∫=t

dTKTHtM ττ

218

Where ))(,( THtM is the maturity at age t after temperature history )(TH , τ is the

age of maturing, varying from 0 to actual age t, and )(TK is the rate function

which depends on the temperature T of the concrete.

The equivalent age concept will be introduced later. For a concrete having a given

maturity after a given temperature history, it is defined as the time during which

the concrete should be placed at a reference constant temperature (usually average

ambient temperature) to reach the same level of maturity. Mathematically, one can

have:

)2.8.....(........................................).........,())(,( re TtMTHtM =

where ),( re TtM is the maturity at age te at constant reference temperature Tr. te is

the equivalent age. By substituting Equation (8.1) in Equation (8.2) to obtain

Equation (8.3):

)3.8.......(..................................................)(),(0

τdTKTtMet

rre ∫=

)4.8...(..........)()].([)())((000

er

t

r

t

r

t

tTKdTKdTKdTKee

=== ∫∫∫ ττττ

From Equations (8.2), (8.3) and (8.4):

219

)5.8.(............................................................)())((

0

ττ dTKTKt

r

t

e ∫=

The Arrhenius law can be used to determine equivalent age:

)6.8....(..................................................)..........

exp(.)(TREaATK −

=

where Ea is the apparent activation energy of the process (in J/mol), T is the

absolute temperature (in K), R is the universal gas constant (8.314 J/mol K) and

A is the constant of the function. The associated equivalent age function can be

obtained by substituting Equation 8.6 in Equation 8.5:

)7.8..(............................................................])(

11][exp[.0

ττ

dTTR

EaAtr

t

e −= ∫

From this equation, there is a synergic effect of activation energy and temperature

combined with time on the equivalent age of polymer concrete. Those

mathematical indications can be validated by experimental results.

220

8.3 Datum temperature

Datum temperature can be defined as the temperature below which strength

development ceases. A low datum temperature is an indication of low activation

energy (Ea). The catalyst amount may help in lowering the activation energy of PC

resin binder (Lee et al., 1997). An increase in catalyst concentration will accelerate

the reaction through the reduction of activation energy and lower the datum

temperature.

8.4 Estimation of datum temperature

Maturity for ordinary cement concrete is defined as an integral of the curing

period and temperature of cement concrete above a datum temperature, and is

expressed by the following equations (Saul, 1951):

The rate constant

)8.8.......(............................................................)())(( οττ TTTK −=

where οT is the datum temperature. When the maturing process is isothermal

)9.8.(................................................................................)( TT =τ

The maturity cM according to the definition will be as follows:

)10.8.......(......................................................................)(0

το dTTMt

c −= ∫

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)10.8.........(............................................................)( το ∆−= ∑ TTMc

where Mc=Maturity [(oC.h) or (oC.d)] of cement concrete at a curing period or age,

t or Δτ (hours or days), T =temperature (oC) of maturing ordinary concrete, and

To = datum temperature (oC) below which there is no strength gain in the cement

concrete, regardless of the curing period. Lee et al. considered τ∆ as a

replacement of τ∆ in Equation 8.10 because of more rapid progress of the setting

or hardening process of rein binder in PC than the cement mortar in ordinary

concrete (Lee et al., 1997). This modification in maturity equation is required due

to the fact that greater strength development can be obtained in hardening process

of PC than cement concrete. Therefore, maturity for PC ( pcM ) can be expressed as

follows:

)11.8.........(............................................................)( το ∆−= ∑ TTM pc

For isothermal reaction (T=Constant)

8.5 Experimental studies of polymer concrete maturity

The reason for nominating flexural strength rather compressive strength was that

a PC base acts as a simply supported beam and the main effective strength is

therefore flexural strength. Compressive strength cannot be an efficient

measurement, as the compressive load is very small compared to the flexural load.

PC samples were prepared according to the method described in Section 3.6.1. To

study flexural strength under various temperatures and times, samples were

222

matured using a Thermoline dehydrator oven TD-150, made in Australia. The

samples were matured using the dehydrator oven at 35 and 50 °C. Small

temperatures, such as 5°C, were achieved by using a 400L Samsung refrigerator.

Ambient maturing took place at room temperature which was an average of

23.1°C. Various times of maturing were applied for each sample, starting with a

minimum of six hours, to a maximum of two weeks. Once the maturing process

was accomplished for a PC sample, a four-point flexural test was performed

according to the Australian standard AS 1012.11-2000 to determine the flexural

strength of the PC sample for a specific time and temperature. The test method

was described in Section 3.6.3. All tests were run at ambient temperature half an

hour after removing the samples from the oven or the fridge. A temperature check

was performed on the PC sample prior to the flexural strength test. This procedure

was to ensure that the PC sample had reached the thermal equilibrium with

ambient temperature at the time of testing. Figure 8.1 shows the development of

flexural strength for various maturing temperatures. Increasing the temperature

increases the level of flexural strength development, which reduces the time for

maturing.

223

Figure 8.1 Flexural strength of the PC as a function of maturing time at various maturing temperatures: ambient, 5 °C, 35 °C and 50°C.

The maximum flexural strength developed was 17.12 MPa, requiring 720 hours

when the maturing temperature was 5 °C, as shown in Figure 8.1. The minimum

strength measured at 50°C was 22.49 MPa, developed over 6 hours, as shown in

Figure 8.1. Assuming that the rate of strength development for the first six hours

is constant when the maturing temperature is 50 °C. Hence, the time required to

develop 17.12 MPa at 50 °C is 4 hours and 34 minutes. By comparing this time

with the time required for strength development at 5 °C, the following can be seen:

by increasing the temperature from 5 °C to 50 °C, the time of the curing has

decreased 157.65 times.

224

8.6 Relative flexural strength

The PC relative flexural strength in maturity operation can be defined as the ratio

of the strength of a PC sample, matured at a particular temperature, and the

maximum strength achieved by an identical PC sample for the same maturing

temperature. The flexural strength was obtained for each temperature and time.

The relative strength was calculated according to the definition. Figure 8.2

displays the relation between relative flexural strength and maturing time for

50°C. The experimental results indicated the elevated temperature effect on the

rate of PC maturing.

0

0.2

0.4

0.6

0.8

1

1.2

0 200 400 600 800

Rela

tive s

treng

th

Time of maturing (hours)

Figure 8.2 Relative strength of PC as a function of maturing time at 50 °C.

The overall relation between maturing time‘t’ (days) and relative strength σrel can

be described empirically utilizing the following expression:

225

)12.8.......(........................................).........tanh(. ktrel =σ

where tan h is the hyperbolic tangent ( xx

xx

eeeex

−

−

+−

=tanh ), and k is the coefficient

that can be calculated for a particular relative strength and time. Plotting the k

coefficient per day for each temperature, as shown in Figure 8.3, revealed a

relationship connecting k with the temperature.

Figure 8.3 revealed a relationship connecting k with the temperature.

The empirical relationship that governs the relative flexural strength with the

maturing temperature and maturing time can be represented as following:

)13.8....(........................................).........)57.0*035.0(tanh(. tTrel +=σ

226

Figure 8.4 displays the experimental results of relative strength for each time and

maturing temperature and the predicted results using the above formula for

relative strength as a function of maturing time. All figures predicted and the

experimental values are reasonably close.

0

0.2

0.4

0.6

0.8

1

1.2

0 5 10 15 20 25 30

Rela

tive

stre

ngth

Time, days

Figure 8.4 Relative strength versus maturing time for 5°C maturing temperature (◊) experimental data and red curve predicted by the empirical formula.

227

0

0.2

0.4

0.6

0.8

1

1.2

0 5 10 15 20 25 30

Rela

tive

stre

ngth

Time, days

Figure 8.5 Relative strength versus maturing time for 35°C maturing temperature (◊) experimental data and red curve predicted by the empirical formula.

0

0.2

0.4

0.6

0.8

1

1.2

0 5 10 15 20 25 30

Rela

tive

stre

ngth

Time, days

Figure 8.6 Relative strength versus maturing time for 50°C maturing temperature (◊) experimental data and red curve predicted by the empirical formula.

228

The datum temperature can be estimated by utilizing the definition of datum

temperature, and applying the boundary condition to Equation (8.13). The datum

temperature is the temperature where the developed strength is zero, in other

words, the relative strength is zero. This leads to K coefficient being equal to zero.

To satisfy this condition:

)14.8(..............................057.0*035.0 =+οT

)15.8..(..............................).........035.057.0(−=οT

)16.8(........................................3.16 CT °−=ο

The ordinary concrete datum temperature is -10 °C (Bergstorm, 1953). Polymer

concrete has a lower datum temperature than ordinary concrete, which also

validates the Equation (8.13). The empirical Equation (8.13) allows obtaining the

maturing time for a particular curing temperature at a certain known level of

relative strength.

8.7 Moisture effect on the resin mechanical properties during

maturing

The effect of moisture was investigated thoroughly and described in chapter

seven, but the effect of maturity was not described there. The resin binder is the

backbone of the composite material and seems to be the most effected by moisture

during maturing, as shown in Figure 8.7. This effect is reflected on in the overall

mechanical properties of a polymer concrete composite material. Samples of resins

229

was prepared in the same way that used in preparing resin sample for moisture

study, the level of moisture was 1%. Resin sample were placed in oven for a day

for various temperatures. It was observed that increasing the maturing

temperature in presence of a low level of moisture resulted in an increased

number of cracks and voids, as displayed in Figure 8.7.

Figure 8.7 Moisture 1%, increase the maturing temperature increased the cracks and voids in UPE resin binder.

During the curing of UPE resin there was a temperature build-up due to the

exothermal reaction. The generated energy during the exothermic reaction was the

fundamental source of chemical energy used in evaporating water that included in

the resin in the course of curing. This resulted in the formation of pores (voids)

that affected the mechanical properties of the resins. Evaporation of water droplets

created voids with a spherical shape, as shown previously. This situation occurred

230

when the only energy available during the reaction was the exothermal energy.

When the reaction energy combined with an external source of energy (maturing

temperature) in the presence of moisture, the effect could be doubled or tripled,

depending on power level of the combined energy source. The water droplets

evaporated quicker and earlier during the curing of the resin with a higher

pressure, causing more voids with a bigger volume and higher numbers of cracks

as the temperature increased. Increasing the level of moisture brought an increase

in the level of voids and cracks populations as shown in Figure 8.8. The main

reason of using maturing process for polymer concrete is to enhance the

mechanical properties and reduce the lead time for maturing. The presence of

moisture induces a catastrophic result in terms of mechanical properties and

undoubtedly increased the lead-time (maturing time).

Figure 8.8 Moisture 2% shows a higher level of cracks and void populations in UPE resin binder.

231

8.8 Conclusions

The following conclusions were drawn from the results:

§ An empirical mathematical expression was developed to predict the

correlation of the relative flexural strength with temperature, as well as the

time of curing.

§ Datum temperature can be calculated using an empirical mathematical

model.

§ Increasing the temperature from 5 °C to 50 °C decreased the time of the

curing by 157.65 times. Adapting the curing process in the production of a

base could reduce the lead-time and enhance the quality.

§ Existence of water diminishes the resin and PC mechanical properties two

or three times as the maturing temperature increases.

232

Chapter 9

9 Conclusions

9.1 Introduction

The principal objective of this research was to optimize the PC composite

materials to be used in manufacturing bases of precision tool machinery. Using

composite materials for such an application in an optimized form can produce

numerous enhancements to elevate the precision level of the machinery and

increase the productivity of the PC base. The research work involved in the PC

optimization was designed according to specific optimization criteria that were

carefully identified according to application requirements. The main focus of this

research was the optimization of the thermal and mechanical properties of PC

bases, and the process of production of a PC for use in the manufacture of PC

bases. For the optimization of the final properties, several critical performance

parameters are nominated. The main parameters include the CTE, the damping

ratio, and the flexural strength of the PC and resin binder. For optimization the

process of the resin binder, the critical performance parameters are viscosity and

temperature. Optimized PC offers improved mechanical, thermal and rheological

properties. It can deliver desirable properties and produce further enhancement in

the accuracy of precision tool machinery. The validation of the optimized PC base

233

using simulation demonstrates the potential to enable precision tool machines to

produce enhanced products in terms of the precision level that can be achieved in

producing further products. This enhancement of the operational conditions for

precision tool machining increases the level of precision for a wider range of

products, reaching a higher peak for these precise products.

9.2 Major Findings and Original Contributions

I. The chemical composition of the thermosetting resin binder has been

optimized, since it is the backbone of a PC composite. Extensive thermal,

mechanical and rheological studies were carried out, as detailed in

Chapter 4. The optimum resin binder composition is nominated as 40%

/60% ARAPOL/MMA. It has the highest damping factor (4.5%) of all the

investigated resins. The highest flexural strength is reached using the

optimum resin with 128 MPa and a low strain of 10.4. It also has the

highest tensile strength. The optimum resin achieves the second lowest

CTE of (7.98 ×10-5°C-1). The nominated resin also has a low rate of

viscosity increase and low temperature profile during curing. The

rheological properties of the optimum resin may also enhance the mixing

of the aggregate with the resin by giving more time prior to gelation,

when the polymerizing mixture is still a flowing liquid. This is the

fundamental contribution that laid the groundwork for further

investigations of the composition of the filler, as detailed in Chapter 5. The

developed polymeric binder has met the research object put forward in

section 1.6.

234

II. The most challenging stage in the study was to nominate and validate the

optimum filler composition according to the optimization criteria of the

application. Some new and unique compositions were investigated for the

first time, such as basalt, spodumene and fly ash and gravel, spodumene

and fly ash. The optimum composition is basalt, sand and fly ash (87%

filler and 13% resin), which has the lowest CTE and acceptable flexural

strength considering the structural load of the application. A reduction in

resin of 4% from 17% down to 13% reduces the PC damping ratio by

approximately 40%. This reduction in damping ratio can be dealt with and

substituted by the structural solution of increasing the damping ratio of

the base. This could be achieved by attaching a single or multiple

mechanical dampers in suitable positions on the PC base. The optimum

filler composition is extremely cost effective compared to other

comparable compositions. Through the validation of the optimum

composition using FEA, the variations in deformation of the rail base were

reduced to a sufficiently low level that they could be ignored. The

optimized PC’s properties and its functionalities are not offered by

existing feedstock materials. The optimal composition of PC, in terms of

resin and composite material, has been determined on the basis of the

potential use by the industrial partner. Details of this were outlined in

Chapter 5. The optimum composition has met the research objectives

.

235

III. Aspects of moulding technology have been examined individually as part of

the process optimization. Each one has a different effect and influences the

mechanical properties and curing behaviour of PC by various means. The

optimum vibration frequency for the operation of a vibration table for the

preparation of a PC sample was identified as 18.9375 Hz. An empirical

relationship correlating the moulding temperature and the DMA amount was

obtained. An increased DMA fraction in the resin binder has a negative

impact on the mechanical properties and increases the curing rate as well as

the temperature profile. Various mixing technologies were investigated for the

purpose of obtaining one that could produce a PC with the highest flexural

strength. It was found that MT1 is the mixing technology that can produce a

PC sample with a flexural strength of 22.53 MPa, which is the maximum

flexural strength compared to the others. Details were outlined in Chapter 6.

This finding has met the research objective in terms of developing the

moulding technology and other related aspects.

IV. Extensive experiments were carried out to fully characterize the effect of

moisture on the thermal, mechanical and curing behaviour of the polymeric

matrix and PC composite material. An increase in the moisture causes an

increase in the curing time and hence reduces the curing rate rapidly. The

effects of moisture on the mechanical properties of the resin domain (flexural

strength, tensile strength, modulus of elasticity and hardness) are large and

clearly apparent. An increase in moisture decreases the mechanical strength of

the resin domain because of the morphological change caused by the increase

in voids and micro-cracks. The DMA results emphasize the increase in the

damping factor when there is an increase in the moisture content of the resin

domain. The CTE of the polymeric matrix increases as the water content

236

increases. The influence of moisture on the main mechanical properties of the

PC composite system has been revealed. An increase in moisture leads to a

decrease in both the flexural and compressive strength at different rates. The

CTE of the polymer concrete composite strength increases up to 50% as

moisture content reaches 5%. FTIR spectroscopy scans show an interaction

between water and the functional groups of the resins. Increasing the water

content increases the level of non-interactive water (bulk water). When 1% of

water is added to the resin composition, the share of MMA solubility (1.2

×60%) is 0.72% and the share of Dimethyl aniline (DMA)(1.5%×0.02%) is

0.03%, and these components are soluble, as shown in Table 7.1. The total

soluble water is 0.75%. In another words, the resin will reach saturation when

the water added is 0.75%of the resin volume and the rest in bulk water, since

the resins reach saturation when the water content is approximately 0.75%.

The existence of water in the particulate fillers can have a catastrophic effect

on both the productivity of a polymer concrete structure and the end-use

mechanical properties. Drying of aggregate fillers which are affected by

moisture should be an essential procedure for raw material preparation, and

the allowable moisture must be as close to zero as possible. 0.002% would be

an acceptable level of moisture in the aggregates used in the manufacture of

PC composite material. Details were outlined in Chapter 7. The results

presented in this chapter meet the objectives of the research in terms of

identification of acceptable moisture content for the fillers, based on the

influence of moisture on the thermo-mechanical properties of both composite

and matrix.

V. Finally, a maturity study has been successfully conducted for PC used in the

bases of precision tool machinery, for the purpose of increasing productivity

and reducing the curing time. An empirical mathematical expression to

237

predict the correlation of the relative flexural strength with temperature as

well as time of curing has been developed. Datum temperature was calculated

using a mathematical model developed empirically. By increasing the

temperature from 5 °C to 50 °C, the time required for curing decreased 157.65

times. Adapting the curing process in the production of a base could reduce

the lead-time and enhance the quality. The existence of water in the resin

diminishes the mechanical properties as the maturing temperature increases.

The outcome of Chapter 8 has met the research objective in terms of

developing a customized maturity method that relates to the PC base for a

precision tool machine.

9.3 Recommendation and Future Work

PC has low thermal conductivity, which affects its thermal, mechanical and curing

behaviour. Increasing the thermal conductivity has the potential to enhance the

thermal, mechanical and curing behaviour of the PC. Emerging technologies

enable the production of inexpensive and affordable nano-fibres, nano-particles

and micro-particles, and the development of nano-composites offers a potential

new generation of PC material that can be used for the bases of precision tool

machinery. For example:,

§ Carbon graphite could offer a very affordable option, as could the

utilisation of fillers such as silica fume fiber glass, fiber carbon and fiber

polypropylene. However, certain challenges continue to hamper the

development of such materials and therefore more rigorous research is

required for an optimized thermal conductivity level.

238

§ These choices include nano-carbon fibres, nano-carbon tubes, micro-carbon

and commercial graphite, all of which can be combined with a particular

design modification of the base to achieve multi-encasements for the base.

These base design modifications include the implementation of conformal

cooling channels in multi-layers, which would enable the base to be further

improved in terms of CTE with the enhancement of temperature

distribution.

§ The attachment of mechanical dampers could induce an improvement of in

the overall structural damping ratio of precision tool machinery. These are

exemplary candidates for the development of new, higher thermal

conductivity, lower CTE and higher flexural strength nano-composites or

micro-composite PCs for use in the bases of precision tool machinery.

§ The time-dependant behaviour of polymer concrete, based on polyester

resin, also influences the behaviour of precision machine bases. Properties

such as the creep and shrinkage of PC bases and how these affect the

stability of the application should be investigated in future research.

§ Further research is required in respect of the compaction of PC, considering

the resin rheological, mechanical properties of the PC and the filler

composition. In addition the uniformity of the PC mixture should be

measured for future research.

§ In Chapter 7, the focus was on the moisture contents of fillers. Water

absorption of aggregates is another aspect that can be recommended for

future research.

239

References

ACI 1972. Recommended practice for measuring, mixing, transporting, and placing concrete. Farmington Hills, Mitch, USA: ACI.

ACI 1986. Guide for use of polymers in concrete. Detroit: American Concrete Institute.

AHN, N. 2004. Effects of diacrylate monomers on the mechanical properties of polymer concrete made with wet aggregates. Journal of Applied Polymer Science, 94, 1077-1085.

AHN, N. 2006. Effects of metallic monomer powders on the mechanical properties of hardened polyester and acrylic polymer concrete. Journal of Applied Polymer Science, 101, 3106-3113.

ALZAYDI, A. A., SHIHATA, S. A. & ALP, T. 1990. The compressive strength of a new ureaformaldehyde-based polymer concrete. Journal of Materials Science, 25, 2851-2856.

ANCA. 2009. Confidance [Online]. Australia, Bayswater ANCA. Available: http://www.anca.com/Home [Accessed March 3, 2012].

ANCA. 2011. TapX - Huge savings in tap production [Online]. Australia, Bayswater: ANCA Available: http://www.anca.com/News/The-Sharp-E-Newsletter/Mar-2011/TapX---Huge-Savings-in-Tap-Production-by-Scrapping [Accessed May 15, 2012].

ANDRIES 1965. Resin concretes Rilem Symposium by Corespondence. Paris.

ATHIJAYAMANI, A., THIRUCHITRAMBALAM, M., NATARAJAN, U. & PAZHANIVEL, B. 2009. Effect of moisture absorption on the mechanical properties of randomly oriented natural fibers/polyester hybrid composite. Materials Science and Engineering: A, 517, 344-353.

ATTA, A. M., ELNAGDY, S. I., ABDEL-RAOUF, M. E., ELSAEED, S. M. & ABDEL-AZIM, A.-A. A. 2005. Compressive properties and curing behaviour of unsaturated polyester resins in the presence of vinyl ester resins derived from recycled poly (ethylene terephthalate). Journal of Polymer Research, 12, 373-383.

240

BAI, W., ZHANG, J., YAN, P. & WANG, X. 2009. Study on vibration alleviating properties of glass fiber reinforced polymer concrete through orthogonal tests. Materials & Design, 30, 1417-1421.

BARBUTA, M., HARJA, M. & BARAN, I. 2010. Comparison of mechanical properties for polymer concrete with different types of filler. Journal of Materials in Civil Engineering 695-701.

BERGSTORM, S. G. 1953. Curing temperature, age and strength of concrete. Magazine of Concrete Research, 5, 61-66.

BLAGA, A. & BEAUDOIN, J. J. 1985. Polymer concrete Canadian Building Digests, 242.

BORCHARDT, H. J. & DANIELS, F. J. 1957. The application of differential thermal analysis to the study of reaction kinetics. Journal of Inorganic and Nuclear Chemistry, 79, 41.

BRANDT, A. 1988. Cement - based composites: materials, mechanical properties and performance, Melbourne, E& FN Spon.

BROCARD, A. & CIRRODE , B. 1967. Fundamental properties of resin concretes. Rilm Symposium by corespondence Paris.

BRONIEWSKI, T. & JAMROZY, Z. Creep of compressive strength in polymer concrete 1st International Congress on Polymer Concrete October 2, 1975 London. 179-184.

BRUCK, H. A. & RABIN, B. H. 1999. Evaluation of rule-of-mixtures predictions of thermal expansion in powder-processed Ni–Al2O3 composites. Journal of the American Ceramic Society, 82, 2927-2930.

BRUNELLE, D. J. 2008. Polyester resin [Online]. Available: http://accessscience.com/content/Polyester%20resins/534200 [Accessed April 4, 212].

BRUNI , C., FORCELLESE, A., GABRIELLI, F. & SIMONCINI, M. 2008. Hard turning of an alloy steel on a machine tool with a polymer concrete bed. Journal of Materials Processing Technology, 202, 493-499.

BUCKNALL, C. B. 1992. Rubber-toughened plastics. Polymer International, 29, 70-70.

BURLESON, J. D. 1974. An Investigation of polymer-aggregates composites for castable building materials. Ph.D Research, Rice University.

241

CARINO, N. J. & LEW, H. S. 2001. The maturity method: from theory to application. In: PETER, C. & CHANG, T. P. (eds.) Structures Congress & Exposition. Washington, D.C., USA: National Institute of Standards.

CHANG, T. P. & STEPHENS, H. L. 1975. Physical properties of premixed polymer concrete. ASCE Journal (Structural Devision), ST11, 2293 - 2302.

CHAWLA, K. K. 1988. Ceramic matrix composite, London, Champman & Hall.

CHEN, B. & LIU, J. 2005. Contribution of hybrid fibers on the properties of the high-strength lightweight concrete having good workability. Cement and Concrete Research, 35, 913-917.

CHERIAN, A. B., ABRAHAM, B. T. & THACHIL, E. T. 2006. Modification of unsaturated polyester resin by polyurethane prepolymers. Journal of Applied Polymer Science, 100, 449-456.

CHERIAN, A. B. & THACHIL, E. T. 2003. Blends of unsaturated polyester resin with functional elastomers. Journal of Elastomers and Plastics, 35, 367-380.

CORTES, F. & CASTILLO, G. 2007. Comparison between the dynamical properties of polymer concrete and grey cast iron for machine tool applications. Materials Design, 28, 1461-1466.

CORTÉS, F. & CASTILLO, G. 2007. Comparison between the dynamical properties of polymer concrete and grey cast iron for machine tool applications. Materials & Design, 28, 1461-1466.

CZARNECKI, L. G., A.; LUKOWSKI, P.; CLIFTON, J. R. 1993. Materail model polymer concete the basis for optimization Beton I Zelezobetohn 2, 18-20.

CZARNECKI, L. G., A.; LUKOWSKI, P.; CLIFTON, J. R. 1999. Optimization of Polymer Concrete Composites. Final Report. National Technical Information Service (NTIS), Technology Administration, U.S. Springfield, VA 22161

DAVYDOV, S. S. 1972 Investigation of polymer concrete and steel polymer concrete Beton I Zhelez Beton, 1-5.

242

DE LA CABA, K. 1999. Fracture behavior-morphology relationships in an unsaturated polyester resin modified with a liquid oligomer. Journal of Polymer Science, Part B: Polymer Physics, 37, 1677-1685.

DEMIRBOGA, R. & GUL, R. 2003. The effects of expanded perlite aggregate, silica fume and fly ash on the thermal conductivity of lightweight concrete. Cement and Concrete Research, 33, 723-727.

DHARMARAJAN, N. 1987. Flextural creep bhavior of polymer concrete system. Ph.D, Rice University.

DING, J. Composite concrete bed for CNC machine tool. Measuring Technology and Mechatronics Automation (ICMTMA), 2010 International Conference on, 13-14 March 2010 2010. 805-807.

DOPPER, J., CLEMENS, M., EHRFELD, W., JUNG, S., KÄMPER, K. P. & LEHR, H. 1997. Micro gear pumps for dosing of viscous fluids. Journal of Micromechanics and Microengineering, 7, 230-232.

EL-HAWARY, M. M. & ABDEL-FATTAH, H. 2000. Temperature effect on the mechanical behavior of resin concrete. Construction and Building Materials, 14, 317-323.

EMA, S. & MARUI, E. 2003. Heoretical analysis on chatter vibration in drilling and its suppression. Journal of Material.and Process Technology, 138, 572-578.

FINK, J. K. 2005. Unsaturated polyester. Reactive Polymers Fundamentals and Applications. Norwich, NY: William Andrew Publishing.

FLANDRO, A. W. 1960. The use of polyester resin in lieu of cement in concrete Cement and Concrete Research. Fort Douglas, Utah: R&D unit (Reinf-Ting) USAR Centter.

FONTANA, J. J. & REAMS, W. 1985. The effect of moisture on the physical and durability properties of methyl methacrylate polymer concrete. Amarican Concrete Institute

FOWLER, D. W. Polymers in concrete where have we been and where are we going? . In: FOWLER, D., ed. ICPIC June 17 2003. ACI, 111-118.

FROCK, H. N. 1987. Particle size distribution. In: COMSTOCK, M. J. (ed.) Particle Size Distribution. American Chemical Society.

243

FURNAS, C. C. 1931. Grading aggregates - I. - mathematical relations for beds of broken solids of maximum density. Industrial & Engineering Chemistry, 23, 1052-1058.

GALE, C. 2008. Composite frame machining center claims higher performance. Modern Machine Shop. http://www.highbeam.com: Gardner Publications Inc.

GAN, L. M., LEE, K. C., CHEW, C. H., NG, S. C. & GAN, L. H. 1994. Copolymerization of styrene and methyl methacrylate in ternary oil-in-water microemulsions: Monomer reactivity ratios and microstructures by 1H NMR and 13C NMR. Macromolecules, 27, 6340.

GANGLANI, M., CARR, S. H. & TORKELSON, J. M. 2002. Influence of cure via network structure on mechanical properties of a free-radical polymerizing thermoset. Polymer, 43, 2747-2760.

GAO, J., DONG, C. & DU, Y. 2009. Nonisothermal curing kinetics and physical properties of unsaturated polyester modified with EA-POSS. International Journal of Polymeric Materials, 59, 1-14.

GAWDZIK, B., KSIȨZOPOLSKI, J. & MATYNIA, T. 2003. Synthesis of new free-radical initiators for polymerization. Journal of Applied Polymer Science, 87, 2238-2243.

GORNINSKI, J., DALMOLIN, D. & KAZMIERCZAK, C. 2007. Strength degradation of polymer concrete in acidic environments. Cement and Concrete Composites, 29, 637-645.

GORNINSKI, J. P., DAL MOLIN, D. C. & KAZMIERCZAK, C. S. 2004. Study of the modulus of elasticity of polymer concrete compounds and comparative assessment of polymer concrete and portland cement concrete. Cement and Concrete Research, 34, 2091-2095.

HADDAD, M. U., FLOWLER, D. W. & PAUL, D. R. 1983. Factors affecting curing and strength of polymer concrete. ACI JOURNAL, 80, 396-402.

HANEMANN, T., SCHUMACHER, B. & HAUBELT, J. 2010. Polymerization conditions influence on the thermomechanical and dielectric properties of unsaturated polyester-styrene-copolymers. Microelectronic Engineering, 87, 15-19.

HAQUE, E. & ARMENIADES, C. D. Montmorillonite polymer concrete : zero shrinkage and expanding polymer concrete with enhanced strength 1985. 1239-1242.

244

HELAL, M. 1978. Experimental study of mechanical properties and structural application of polymer concrete. Ph.D, Rice University, USA.

HOJO, H., TSUDA, T., OGASAWARA, K. & TAKIZAWA, T. 1986. Corrosion behaviour of epoxy and unsaturated polyester resins in alkaline solution Polymeric Materials for Corrosion Control 314-326.

HOWDYSHELL, P. A. 1972. Creep charactiristics of polyester concrete Champaign,illinoise: Construction Engineering Laboratory.

HUMMEL, F. A. 1950. Observation on the thermal expansion of crystalline and glassy substances. Journal of American Ceramic Society, 33, 103-107.

IDES. 2013. The plastic Web [Online]. Available: http://www.ides.com [Accessed 29/07 2013].

IGNACIO, C., FERRAZ, V. & OREFICE, R. L. 2008. Study of the behavior of polyester concretes containing ionomers as curing agents. Journal of Applied Polymer Science, 108, 2682-2690.

J.GRAHAM 1975. Mineralogical notes on α-Spodumene. The American mineralogist, 60, 919-923.

JO, B.-W., PARK, S.-K. & PARK, J.-C. 2008. Mechanical properties of polymer concrete made with recycled PET and recycled concrete aggregates. Construction and Building Materials, 22, 2281-2291.

JO, B.-W., TAE, G.-H. & KIM, C.-H. 2007. Uniaxial creep behavior and prediction of recycled-PET polymer concrete. Construction and Building Materials, 21, 1552-1559.

KATTAS, GASTROCK, F., I., L. & A., C. 2004. Plastic Additives. In: A., C. & HARPER (eds.) Modern Plastics Handbook. London McGraw-Hill.

KHRISTOVA, Y. & ANISKEVICH, K. 1995. Prediction of creep of polymer concrete. Mechanics of Composite Materials, 31, 216-219.

KILIC, A., ATIS, C. D., TEYMEN, A., KARAHAN, O., AZCAN, F., BILIM, C. & OZDEMIR, M. 2008. The influence of aggregate type on the strength and abrasion resistance of high strength concrete. Cement and Concrete Composites, 30, 290-296.

245

KIM, H. S., PARK, K. Y. & LEE, D. G. 1995. A study on the epoxy resin concrete for the ultra-precision machine tool bed. Journal of Materials Processing Technology, 48, 649-655.

KNAB, L. I. Polyester concrete: load rate variance. Hyway Research Record, 1969 500 Fifth Street, NW

Washington, DC 20001 USA. Highway Research Board, 19-31.

KNAB, L. I. 1972. Flexural Behaviour of Conventionally Reinforced Polyester Concrete Beams Phd, University of Cincinnati, USA.

KNAB, L. I., CLIFTON, J. R. & INGS, J. B. 1983. Effects of maximum void size and aggregate characteristics on the strength of mortar. Cement and Concrete Research, 13, 383-390.

KUKACKA, L. E. & DEPUY, G. W. 1974. Concrete polymer mterial - fifth topical report. National Technical Information Service, Department of Commerce, Virginia, USA: Radiation Division, department of applied sceince brookhaven national labratory and associated university.

LAMOND, J. F. & PIELERT, J. H. 2006. Significance of tests and properties of concrete and concrete-making materials. MA, USA: ASTM International.

LAU, D. & BUYUKOZTURK, O. 2010. Fracture characterization of concrete/epoxy interface affected by moisture. Mechanics of Materials, 42, 1031-1042.

LEE, D. G., DO SUH, J., SUNG KIM, H. & MIN KIM, J. 2004. Design and manufacture of composite high speed machine tool structures. Composites Science and Technology, 64, 1523-1530.

LEE, Y. S., OHAMA, Y., DEMURA, K. & YEON, K. S. An empirical approach for predicting compressive strength of lightweight polyester mortars the maturity method The Second East Asia Symposium on Polymers in Concrete (II-EASPIC), 1997 Japan. London: E&FN Spon, 76-84.

LI, P., YANG, X., YU, Y. & YU, D. 2004. Cure kinetics, microheterogeneity, and mechanical properties of the high-temperature cure of vinyl ester resins. Journal of Applied Polymer Science, 92, 1124-1133.

LI, S., HU, J., SONG, F. & WANG, X. 1996. Influence of interface modification and phase separation on damping properties of epoxy concrete. Cement and Concrete Composites, 18, 445-453.

246

LIU, C.-H., YU, T. L. & CHEN, C.-C. 2002. Effect of curing temperature on the morphology of unsaturated polyester resin blended with poly(vinyl acetate). Polymer Engineering & Science, 42, 567-581.

LOKUGE, W. & ARAVINTHAN, T. 2013. Effect of fly ash on the behaviour of polymer concrete with different types of resin. Materials & Design, 51, 175-181.

LU, S., WEI, C. & YANG, X. 2006. A novel chain-extended urea containing hyperbranched polymer used as toughening modifier for epoxy resin. Transactions of Nonferrous Metals Society of China, 16, s665-s670.

MAHDI, F., ABBAS, H. & KHAN, A. A. 2010. Strength characteristics of polymer mortar and concrete using different compositions of resins derived from post-consumer PET bottles. Construction and Building Materials, 24, 25-36.

MAHDI, F., KHAN, A. & ABBAS, H. 2007. Physiochemical properties of polymer mortar composites using resins derived from post-consumer PET bottles. Cement and Concrete Composites, 29, 241-248.

MAKSIMOV, R. D., JIRGENS, L., JANSONS, J. & PLUME, E. 1999. Mechanical properties of polyester polymer-concrete. Mechanics of Composite Materials, 35, 99-110.

MASPOCH, M. L. L. & MARTINEZ, A. B. 1998. Toughening of unsaturated polyester with rubber particles. Part I: Morphological study. Polymer Engineering & Science, 38, 282-289.

MCINTOSH, J. D. 1949. Electrical curing of concrete. Magazine of Concrete Research, 1, 21-28.

MCKEOWN, P. A. & MORGAN, G. H. 1979. Epoxy granite: a structural material for precision machines. Precision Engineering, 1, 227-229.

MICHAYLOV 1989. Polymer concrete and building structurs Moscow, Stroyisdat.

MICHEL, B. 2007. Thermosets and composites: technical information for plastics users, Les Ulis, France, Elsevier.

MORGAN, G. H. & MCKEON, A. 1979. Materials for machine tool structures. 20th International Machine Tool Design and Research Confrence 1979 Birmingham. Macmillan Press Limited, 429-434.

247

MOSIEWICKI, M. A., CASADO, U., MARCOVICH, N. E. & ARANGUREN, M. I. 2009. Polyurethanes from tung oil: Polymer characterization and composites. Polymer Engineering and Science, 49, 685-692.

MUN, K. & CHOI, N. 2008. Properties of poly methyl methacrylate mortars with unsaturated polyester resin as a crosslinking agent. Construction and Building Materials, 22, 2147-2152.

MUTHUKUMAR, M. & MOHAN, D. 2004. Optimization of mechanical properties of polymer concrete and mix design recommendation based on design of experiments. Journal of Applied Polymer Science, 94, 1107-1116.

NURSE, R. W. 1949. Steam curing of concrete. Magazine of Concrete Research,, 1, 79-88.

OHAMA, Y. Mix Proportions and properties of polyester resin concrete. Polymer in Concrete, 1973 Detroit, Michigan. American Concrete Institute 283-294.

OHAMA, Y. 1974 Creep of resin concrete and polymer impregnated concrete. . 17th Japan Congress on Mterails Research. Fukushima.

OHAMA, Y. 1979. Effect of coarse aggregates on compressive strength of polyester resin concrete. The International Journal of Cement Composite, 1, 111-115.

OHAMA, Y. & DEMURA, K. 1982. Relation between curing conditions and compressive strength of polyester resin concrete. International Journal of Cement Composites and Lightweight Concrete, 4, 241-244.

OHAMA, Y., DEMURA, K. & KOBAYASHI, T. 1981. Mix proportioning and mechanical properties of polymethyl methacrylate resin concrete. Trans Jpn Concrete Inst.

ORAK, S. 2000. Investigation of vibration damping on polymer concrete with polyester resin. Cement and Concrete Research, 30, 171-174.

ORAK, S. & KARADEMIR, S. 1998. An investigation on the damping characteristic of polymer concrete with polyester resin. Poliester recineli polimer betonun sonum yetenegi uzerine bir arastirma, 22, 323-327.

ORAK, S. & KARADEMIR, S. 2000. Investigation of vibration damping on polymer concrete with polyester resin. cement and concrete Reaserch, 30, 171-174.

PACHPINYO, P., LERTPRASERTPONG, P., CHUAYJULJIT, S., SIRISOOK, R. & PIMPAN, V. 2006. Preliminary study on preparation of unsaturated polyester

248

resin/natural rubber latex blends in the presence of dispersion aids. Journal of Applied Polymer Science, 101, 4238-4241.

PANTELIOU, S. D. & DIMAROGONAS, A. D. 2000. Damping associated with porosity and crack in solids. Theoretical and Applied Fracture Mechanics, 34, 217-223.

PARK, H. W. 2008. Development of micro-grinding mechanics and machine tools. Ph.D. 3308806, Georgia Institute of Technology, USA.

PAUL, D. R., FOWLER, D. W. & HOUSTON, J. T. 1973. Polymerization of methyl methacrylate by catalyzed peroxide decomposition without applied heat. Journal of Applied Polymer Science, 17, 2771-2782.

PETER, J. Damping in machine tool construction. 6th International ofmaterial and technology direct research MTDR, 1965 Macmillan., 191-210.

POWERS, T. C. 1948. A discussion of cement hydration in relationto the curing of concrete

Portland Cement Association, Research Department BulletinRX025

PRIN, D. & CUBAUD 1977. Polyester polymer concrete in civil engineering Material Constructions, 8, 291-304.

RAHMAN, M., MANSUR, M. A., AMBROSE, W. D. & CHUA, K. H. 1987. Design, fabrication and performance of a ferrocement machine tool bed. International Journal of Machine Tools and Manufacture, 27, 431-442.

RAHMAN, M., MANSUR, M. A., LEE, L. K. & LUM, J. K. 2001. Development of a polymer impregnated concrete damping carriage for linear guideways for machine tools. International Journal of Machine Tools and Manufacture, 41, 431-441.

RAMANA REDDY, G. V., PRASAD BABU, Y. P. & RAMI REDDY, N. S. 2002. Microemulsion and conventional emulsion copolymerizations of methyl methacrylate with acrylonitrile. Journal of Applied Polymer Science, 85, 1503-1510.

RAY, D. 2008. Modification of the dynamic damping behavior of unsaturated polyester resin. Journal of Reinforced Plastics and Composites.

RAY, D. 2009. Modification of the Dynamic Damping Behavior of Fly Ash Filled Unsaturated Polyester Resin/SBR Latex Blend Composites. Journal of Reinforced Plastics and Composites, 28, 1537-1552.

249

REBEIZ, M.ASCE, A. P. & CRAFT 2002. Properties of polymer concrete using coal fly ash. Journal of Energy Engineering, 128, 62 – 73.

REBEIZ , K. S. 1996. Precast use of polymer concrete using unsaturated polyester resin based on recycled PET waste. Construction and Building Materials, 10, 215-220.

REBEIZ, K. S. & CRAFT, A. P. 2002. Polymer concrete using coal fly ash. Journal of Energy Engineering, 128, 62-73.

REIS, J. M. L. 2010. Fracture assessment of polymer concrete in chemical degradation solutions. Construction and Building Materials, 24, 1708-1712.

REIS, J. M. L. 2011. Effect of aging on the fracture mechanics of unsaturated polyester based on recycled PET polymer concrete. Materials Science and Engineering: A, 528, 3007-3009.

REIS, J. M. L. & CARNEIRO, E. P. 2011. Evaluation of PET waste aggregates in polymer mortars. Construction and Building Materials.

RODRIGUEZ, E. L. 1993. Effect of reactive monomers and functional polymers on the mechanical properties of an unsaturated polyester resin. Polymer Engineering & Science, 33, 115-121.

SALJE, E. & GERLOFF, H. 1986. Machine Tool Beds Made of Cast Iron or Polymer Concrete. A Comparative Evaluation of their Thermal Performance. Werkzeug maschine ngestelle aus grauguss oder polymerbeton. Vergleichende untersuchung ihres thermischen verhaltens., 128, 595-602.

SANCHEZ, E. M. S., ZAVAGLIA, C. A. C. & FELISBERTI, M. I. 2000. Unsaturated polyester resins: Influence of the styrene concentration on the miscibility and mechanical properties. Polymer, 41, 765-769.

SAUL, A. G. A. 1951. Principles underlying the steam curing of concrete at atmospheric

Pressure. Magazine of Concrete Research, 6, 127-140.

SEMIHA, A. & CENGIZ , D. 2011. Effect of granulated blast furnace slag and fly ash addition on the strength properties of lightweight mortars containing waste PET aggregates. Construction and Building Materials, 25, 4052-4058.

SEZAN, O. 2000. Investigation of vibration damping on polymer concrete with polyester resin. Cement and Concrete Research, 30, 171-174.

250

SHOKRIEH, M. M., HEIDARI-RARANI & KASHIZADEH 2011. Effects of thermal cycles on mechanical properties of an optimized polymer concrete. Construction and Building Materials, 25, 3540-3549.

SIDNEY, H. G. 1986. Handbook of thermoset plastics, NewJersy, USA, Noyes Publications.

SLOMATOVE 1970. Polymer cement concete and polymer concrete Oakridge, Tenn: U.S.A. Atomic Energy Commission

SOFI, M., VAN DEVENTER, J. S. J., MENDIS, P. A. & LUKEY, G. C. 2007. Engineering properties of inorganic polymer concretes (IPCs). Cement and Concrete Research, 37, 251-257.

STRARMENOV, V. L., GOUDEV & MALCEV 1965. Light and ordinary polymer resin concrete Rilem Symposium by corespondance Paris.

SUH, J. & LEE, D. 2008a. Design and manufacture of hybrid polymer concrete bed for high-speed CNC milling machine. International Journal of Mechanics and Materials in Design, 4, 113-121.

SUH, J. D. & LEE, D. G. 2008b. Design and manufacture of hybrid polymer concrete bed for high-speed CNC milling machine. International Journal of Mechanics and Materials in Design, 4, 113-121.

SUZUKI, H. A. S. Fire Tests on models constructed of resin concrete. 1st International Congress on Polymer Concrete, 1975. 306-313.

TECHSPEX. 2008. S22 - Powerful, fast, precise: uncompromisingly good [Online]. Weilheim, Germany: Feinmechanik Michael Deckel. Available: http://www.techspex.com/techspex/grinding/model?grinding_id=2049&units=english [Accessed April 2, 2012].

TOLBERT, R. N. & HACKET, R. M. 1976. Parameter testing of epoxy polymer concrete. Polymer Engineering & Science, 16, 575-578.

TOLBERT, R. N. & HACKT, R. M. 1979. Viscoelastic properties of epoxy polymer concrete. Polymer Engineering & Science, 19, 795-799.

TOULOUKIAN, Y. S. 1977. Thermal expansion nonmetallic solids

251

TUAKTA, C. & BUYUKOZTURK, O. 2011. Deterioration of FRP/concrete bond system under variable moisture conditions quantified by fracture mechanics. Composites Part B: Engineering, 42, 145-154.

TUNC, L. T. & BUDAK, E. 2012. Effect of cutting conditions and tool geometry on process damping in machining. International Journal of Machine Tools and Manufacture, 57, 10-19.

VALORE, R. C. J. & NAUS, D. J. 1975. Resin bound aggregate material systems. Holifield National Laboratory, USA: Holifield National Laboratory.

VARUGHESE, K. T. & CHATURVEDI, B. K. 1996. Fly ash as fine aggregate in polyester based polymer concrete. Cement and Concrete Composites, 18, 105-108.

VIPULANANDAN, C. & PAUL, E. 1990. Performance of Epoxy and Polyester Polymer Concrete. ACI Materail 87, 241-251.

VIPULANANDAN, C. & PAUL, E. 1993. Characterization of Polyester Polymer and Polymer Concrete. Journal of Materials in Civil Engineering, 5, 62-82.

WANG, X., LIU, H. & OUYANG, S. 2008. Damping properties of flexible epoxy resin. Journal of Wuhan University of Technology-Mater. Sci. Ed., 23, 411-414.

WELCH, G. B., CARMICHAEL, A. L. & HATTERSLY 1962. Epoxy resin concrete. Civil Engineering and Public Works Review, 57, 759-762.

WONG, C. P. & BOLLAMPALLY, R. S. 1999. Thermal conductivity, elastic modulus, and coefficient of thermal expansion of polymer composites filled with ceramic particles for electronic packaging. Journal of Applied Polymer Science, 74, 3396-3403.

XU, Z. R., CHAWLA, K. K., MITRA, R. & FINE, M. E. 1994. Effect of particle size on the thermal expansion of TiCAl XC composites. Scripta Metallurgica et Materialia, 31, 1525-1530.

Y.OHAMA, K. D. 1997. Polymer in concrete, E&FN Spon.

YANG, Y.-S. & SUSPENE, L. 1991. Curing of unsaturated polyester resins: Viscosity studies and simulations in pre-gel state. Polymer Engineering & Science, 31, 321-332.

ZASKE, O. C. & GOODMAN, S. H. 1998. Unsaturated polyester and vinyl ester resins. In: GOODMAN, S. (ed.) Handbook of Thermoset Plastics. William Andrew Publishing

252

ZHENG, A., OTA, T., SATO, T., TANAKA, H., SASAI, K. & ZHOU, R. 1988. An ESR study of the curing reaction of unsaturated polyester with vinyl monomers and the thermal behavior of the cured polymers. Journal of Macromolecular Science: Part A - Chemistry, 25, 1-26.

ZHU, H., WU, B., LI, D., ZHANG, D. & CHEN, Y. 2011. Influence of voids on the tensile performance of carbon/epoxy fabric laminates. Journal of Materials Science &Technology, 27, 69-73.